diff --git a/plugins/calendar/calendar_ui.js b/plugins/calendar/calendar_ui.js
index 60d546eb..04c9c761 100644
--- a/plugins/calendar/calendar_ui.js
+++ b/plugins/calendar/calendar_ui.js
@@ -1,4268 +1,4276 @@
 /**
  * Client UI Javascript for the Calendar plugin
  *
  * @author Lazlo Westerhof <hello@lazlo.me>
  * @author Thomas Bruederli <bruederli@kolabsys.com>
  *
  * @licstart  The following is the entire license notice for the
  * JavaScript code in this file.
  *
  * Copyright (C) 2010, Lazlo Westerhof <hello@lazlo.me>
  * Copyright (C) 2014-2015, Kolab Systems AG <contact@kolabsys.com>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU Affero General Public License as
  * published by the Free Software Foundation, either version 3 of the
  * License, or (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  * GNU Affero General Public License for more details.
  *
  * You should have received a copy of the GNU Affero General Public License
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  *
  * @licend  The above is the entire license notice
  * for the JavaScript code in this file.
  */
 
 // Roundcube calendar UI client class
 function rcube_calendar_ui(settings)
 {
     // extend base class
     rcube_calendar.call(this, settings);
 
     /***  member vars  ***/
     this.is_loading = false;
     this.selected_event = null;
     this.selected_calendar = null;
     this.search_request = null;
     this.saving_lock = null;
     this.calendars = {};
     this.quickview_sources = [];
 
 
     /***  private vars  ***/
     var DAY_MS = 86400000;
     var HOUR_MS = 3600000;
     var me = this;
     var day_clicked = day_clicked_ts = 0;
     var ignore_click = false;
     var event_defaults = { free_busy:'busy', alarms:'' };
     var event_attendees = [];
     var calendars_list;
     var calenders_search_list;
     var calenders_search_container;
     var search_calendars = {};
     var attendees_list;
     var resources_list;
     var resources_treelist;
     var resources_data = {};
     var resources_index = [];
     var resource_owners = {};
     var resources_events_source = { url:null, editable:false };
     var freebusy_ui = { workinhoursonly:false, needsupdate:false };
     var freebusy_data = {};
     var current_view = null;
     var count_sources = [];
     var event_sources = [];
     var exec_deferred = 1;
     var sensitivitylabels = { 'public':rcmail.gettext('public','calendar'), 'private':rcmail.gettext('private','calendar'), 'confidential':rcmail.gettext('confidential','calendar') };
     var ui_loading = rcmail.set_busy(true, 'loading');
 
     // global fullcalendar settings
     var fullcalendar_defaults = {
       theme: false,
       aspectRatio: 1,
       timezone: false,  // will treat the given date strings as in local (browser's) timezone
       monthNames: settings.months,
       monthNamesShort: settings.months_short,
       dayNames: settings.days,
       dayNamesShort: settings.days_short,
       weekNumbers: settings.show_weekno > 0,
       weekNumberTitle: rcmail.gettext('weekshort', 'calendar') + ' ',
       firstDay: settings.first_day,
       firstHour: settings.first_hour,
       slotDuration: {minutes: 60/settings.timeslots},
       businessHours: {
         start: settings.work_start + ':00',
         end: settings.work_end + ':00'
       },
       scrollTime: settings.work_start + ':00',
       views: {
         list: {
           titleFormat: settings.dates_long,
           listDayFormat: settings.date_long,
           visibleRange: function(currentDate) {
             return {
               start: currentDate.clone(),
               end: currentDate.clone().add(settings.agenda_range, 'days')
             }
           }
         },
         month: {
           columnFormat: 'ddd', // Mon
           titleFormat: 'MMMM YYYY',
           eventLimit: 4
         },
         week: {
           columnFormat: 'ddd ' + settings.date_short, // Mon 9/7
           titleFormat: settings.dates_long
         },
         day: {
           columnFormat: 'dddd ' + settings.date_short,  // Monday 9/7
           titleFormat: 'dddd ' + settings.date_long
         }
       },
       timeFormat: settings.time_format,
       slotLabelFormat: settings.time_format,
       defaultView: rcmail.env.view || settings.default_view,
       allDayText: rcmail.gettext('all-day', 'calendar'),
       buttonText: {
         today: settings['today'],
         day: rcmail.gettext('day', 'calendar'),
         week: rcmail.gettext('week', 'calendar'),
         month: rcmail.gettext('month', 'calendar'),
         list: rcmail.gettext('agenda', 'calendar')
       },
       buttonIcons: {
        prev: 'left-single-arrow',
        next: 'right-single-arrow'
       },
       nowIndicator: settings.time_indicator,
       eventLimitText: function(num) {
         return rcmail.gettext('andnmore', 'calendar').replace('$nr', num);
       },
       // event rendering
       eventRender: function(event, element, view) {
         if (view.name != 'list') {
           var prefix = event.sensitivity && event.sensitivity != 'public' ? String(sensitivitylabels[event.sensitivity]).toUpperCase()+': ' : '';
           element.attr('title', prefix + event.title);
         }
         if (view.name != 'month') {
           if (view.name == 'list') {
             var loc = $('<td>').attr('class', 'fc-event-location');
             if (event.location)
               loc.text(event.location);
             element.find('.fc-list-item-title').after(loc);
           }
           else if (event.location) {
             element.find('div.fc-title').after($('<div class="fc-event-location">').html('@&nbsp;' + Q(event.location)));
           }
           var time_element = element.find('div.fc-time');
           if (event.sensitivity && event.sensitivity != 'public')
             time_element.append('<i class="fc-icon-sensitive"></i>');
           if (event.recurrence)
             time_element.append('<i class="fc-icon-recurring"></i>');
           if (event.alarms || (event.valarms && event.valarms.length))
             time_element.append('<i class="fc-icon-alarms"></i>');
         }
         if (event.status) {
           element.addClass('cal-event-status-' + String(event.status).toLowerCase());
         }
 
         element.attr('aria-label', event.title + ', ' + me.event_date_text(event, true));
       },
       // callback when a specific event is clicked
       eventClick: function(event, ev, view) {
         if (!event.temp && (!event.className || event.className.indexOf('fc-type-freebusy') < 0))
           event_show_dialog(event, ev);
       }
     };
 
     /***  imports  ***/
     var Q = this.quote_html;
     var text2html = this.text2html;
     var event_date_text = this.event_date_text;
     var date2unixtime = this.date2unixtime;
     var fromunixtime = this.fromunixtime;
     var parseISO8601 = this.parseISO8601;
     var date2servertime = this.date2ISO8601;
     var render_message_links = this.render_message_links;
 
 
     /***  private methods  ***/
 
     // same as str.split(delimiter) but it ignores delimiters within quoted strings
     var explode_quoted_string = function(str, delimiter)
     {
       var result = [],
         strlen = str.length,
         q, p, i, chr, last;
 
       for (q = p = i = 0; i < strlen; i++) {
         chr = str.charAt(i);
         if (chr == '"' && last != '\\') {
           q = !q;
         }
         else if (!q && chr == delimiter) {
           result.push(str.substring(p, i));
           p = i + 1;
         }
         last = chr;
       }
 
       result.push(str.substr(p));
       return result;
     };
 
     // Change the first charcter to uppercase
     var ucfirst = function(str)
     {
         return str.charAt(0).toUpperCase() + str.substr(1);
     };
 
     // clone the given date object and optionally adjust time
     var clone_date = function(date, adjust)
     {
       var d = 'toDate' in date ? date.toDate() : new Date(date.getTime());
 
       // set time to 00:00
       if (adjust == 1) {
         d.setHours(0);
         d.setMinutes(0);
       }
       // set time to 23:59
       else if (adjust == 2) {
         d.setHours(23);
         d.setMinutes(59);
       }
 
       return d;
     };
 
     // fix date if jumped over a DST change
     var fix_date = function(date)
     {
       if (date.getHours() == 23)
         date.setTime(date.getTime() + HOUR_MS);
       else if (date.getHours() > 0)
         date.setHours(0);
     };
 
     var date2timestring = function(date, dateonly)
     {
       return date2servertime(date).replace(/[^0-9]/g, '').substr(0, (dateonly ? 8 : 14));
     }
 
     var format_date = function(date, format)
     {
       return $.fullCalendar.formatDate('toDate' in date ? date : moment(date), format);
     };
 
     var format_datetime = function(date, mode, voice)
     {
       return me.format_datetime(date, mode, voice);
     }
 
     var render_link = function(url)
     {
       var islink = false, href = url;
       if (url.match(/^[fhtpsmailo]+?:\/\//i)) {
         islink = true;
       }
       else if (url.match(/^[a-z0-9.-:]+(\/|$)/i)) {
         islink = true;
         href = 'http://' + url;
       }
       return islink ? '<a href="' + Q(href) + '" target="_blank">' + Q(url) + '</a>' : Q(url);
     }
 
     // determine whether the given date is on a weekend
     var is_weekend = function(date)
     {
       return date.getDay() == 0 || date.getDay() == 6;
     };
 
     var is_workinghour = function(date)
     {
       if (settings['work_start'] > settings['work_end'])
         return date.getHours() >= settings['work_start'] || date.getHours() < settings['work_end'];
       else
         return date.getHours() >= settings['work_start'] && date.getHours() < settings['work_end'];
     };
 
     var load_attachment = function(data)
     {
       var event = data.record,
         query = {_id: data.attachment.id, _event: event.recurrence_id || event.id, _cal: event.calendar};
 
       if (event.rev)
         query._rev = event.rev;
 
       if (event.calendar == "--invitation--itip")
         $.extend(query, {_uid: event._uid, _part: event._part, _mbox: event._mbox});
 
       libkolab.load_attachment(query, data.attachment);
     };
 
     // build event attachments list
     var event_show_attachments = function(list, container, event, edit)
     {
       libkolab.list_attachments(list, container, edit, event,
         function(id) { remove_attachment(id); },
         function(data) { load_attachment(data); }
       );
     };
 
     var remove_attachment = function(id)
     {
       rcmail.env.deleted_attachments.push(id);
     };
 
     // event details dialog (show only)
     var event_show_dialog = function(event, ev, temp)
     {
       var $dialog = $("#eventshow");
       var calendar = event.calendar && me.calendars[event.calendar] ? me.calendars[event.calendar] : { editable:false, rights:'lrs' };
 
       if (!temp)
         me.selected_event = event;
 
       if ($dialog.is(':ui-dialog'))
         $dialog.dialog('close');
 
       // remove status-* and sensitivity-* classes
       $dialog.removeClass(function(i, oldclass) {
           var oldies = String(oldclass).split(' ');
           return $.grep(oldies, function(cls) { return cls.indexOf('status-') === 0 || cls.indexOf('sensitivity-') === 0 }).join(' ');
       });
 
       // convert start/end dates if not done yet by fullcalendar
       if (typeof event.start == 'string')
         event.start = parseISO8601(event.start);
       if (typeof event.end == 'string')
         event.end = parseISO8601(event.end);
 
       // allow other plugins to do actions when event form is opened
       rcmail.triggerEvent('calendar-event-init', {o: event});
 
       $dialog.find('div.event-section, div.event-line, .form-group').hide();
       $('#event-title').html(Q(event.title)).show();
       
       if (event.location)
         $('#event-location').html('@ ' + text2html(event.location)).show();
       if (event.description)
         $('#event-description').show().find('.event-text').html(text2html(event.description, 300, 6));
       if (event.vurl)
         $('#event-url').show().find('.event-text').html(render_link(event.vurl));
       
       // render from-to in a nice human-readable way
       // -> now shown in dialog title
       // $('#event-date').html(Q(me.event_date_text(event))).show();
       
       if (event.recurrence && event.recurrence_text)
         $('#event-repeat').show().find('.event-text').html(Q(event.recurrence_text));
       
       if (event.valarms && event.alarms_text)
         $('#event-alarm').show().find('.event-text').html(Q(event.alarms_text).replace(',', ',<br>'));
       
       if (calendar.name)
         $('#event-calendar').show().find('.event-text').html(Q(calendar.name)).addClass('cal-'+calendar.id).css('color', calendar.textColor || calendar.color || '');
       if (event.categories)
         $('#event-category').show().find('.event-text').html(Q(event.categories)).addClass('cat-'+String(event.categories).toLowerCase().replace(rcmail.identifier_expr, ''));
       if (event.free_busy)
         $('#event-free-busy').show().find('.event-text').text(rcmail.gettext(event.free_busy, 'calendar'));
       if (event.priority > 0) {
         var priolabels = [ '', rcmail.gettext('highest'), rcmail.gettext('high'), '', '', rcmail.gettext('normal'), '', '', rcmail.gettext('low'), rcmail.gettext('lowest') ];
         $('#event-priority').show().find('.event-text').html(Q(event.priority+' '+priolabels[event.priority]));
       }
 
       if (event.status) {
         var status_lc = String(event.status).toLowerCase();
         $('#event-status').show().find('.event-text').text(rcmail.gettext('status-'+status_lc,'calendar'));
         $('#event-status-badge > span').text(rcmail.gettext('status-'+status_lc,'calendar'));
         $dialog.addClass('status-'+status_lc);
       }
       if (event.sensitivity && event.sensitivity != 'public') {
         $('#event-sensitivity').show().find('.event-text').text(sensitivitylabels[event.sensitivity]);
         $('#event-status-badge > span').text(sensitivitylabels[event.sensitivity]);
         $dialog.addClass('sensitivity-'+event.sensitivity);
       }
       if (event.created || event.changed) {
         var created = parseISO8601(event.created),
           changed = parseISO8601(event.changed);
         $('.event-created', $dialog).text(created ? format_datetime(created) : rcmail.gettext('unknown','calendar'));
         $('.event-changed', $dialog).text(changed ? format_datetime(changed) : rcmail.gettext('unknown','calendar'));
         $('#event-created,#event-changed,#event-created-changed').show()
       }
 
       // create attachments list
       if ($.isArray(event.attachments)) {
         event_show_attachments(event.attachments, $('#event-attachments').find('.event-text'), event);
         if (event.attachments.length > 0) {
           $('#event-attachments').show();
         }
       }
       else if (calendar.attachments) {
         // fetch attachments, some drivers doesn't set 'attachments' prop of the event?
       }
 
       // build attachments list
       $('#event-links').hide();
       if ($.isArray(event.links) && event.links.length) {
           render_message_links(event.links || [], $('#event-links').find('.event-text'), false, 'calendar');
           $('#event-links').show();
       }
 
       // list event attendees
       if (calendar.attendees && event.attendees) {
         // sort resources to the end
         event.attendees.sort(function(a,b) {
           var j = a.cutype == 'RESOURCE' ? 1 : 0,
               k = b.cutype == 'RESOURCE' ? 1 : 0;
           return (j - k);
         });
 
         var data, mystatus = null, rsvp, line, morelink, html = '', overflow = '',
           organizer = me.is_organizer(event);
 
         for (var j=0; j < event.attendees.length; j++) {
           data = event.attendees[j];
           if (data.email) {
             if (data.role != 'ORGANIZER' && settings.identity.emails.indexOf(';'+data.email) >= 0) {
               mystatus = (data.status || 'UNKNOWN').toLowerCase();
               if (data.status == 'NEEDS-ACTION' || data.status == 'TENTATIVE' || data.rsvp)
                 rsvp = mystatus;
             }
           }
 
           line = rcube_libcalendaring.attendee_html(data);
 
           if (morelink)
             overflow += ' ' + line;
           else
             html += ' ' + line;
 
           // stop listing attendees
           if (j == 7 && event.attendees.length >= 7) {
             morelink = $('<a href="#more" class="morelink"></a>').html(rcmail.gettext('andnmore', 'calendar').replace('$nr', event.attendees.length - j - 1));
           }
         }
 
         if (html && (event.attendees.length > 1 || !organizer)) {
           $('#event-attendees').show()
             .find('.event-text')
             .html(html)
             .find('a.mailtolink').click(event_attendee_click);
 
           // display all attendees in a popup when clicking the "more" link
           if (morelink) {
             $('#event-attendees .event-text').append(morelink);
             morelink.click(function(e){
               rcmail.simple_dialog(
                 '<div id="all-event-attendees" class="event-attendees">' + html + overflow + '</div>',
                 rcmail.gettext('tabattendees','calendar'),
                 null,
                 {width: 450, cancel_button: 'close'});
               $('#all-event-attendees a.mailtolink').click(event_attendee_click);
               return false;
             });
           }
         }
 
         if (mystatus && !rsvp) {
           $('#event-partstat').show().find('.changersvp, .event-text')
             .removeClass('accepted tentative declined delegated needs-action unknown')
             .addClass(mystatus);
           $('#event-partstat').find('.event-text')
             .text(rcmail.gettext('status' + mystatus, 'libcalendaring'));
         }
 
         var show_rsvp = rsvp && !organizer && event.status != 'CANCELLED' && me.has_permission(calendar, 'v');
         $('#event-rsvp')[(show_rsvp ? 'show' : 'hide')]();
         $('#event-rsvp .rsvp-buttons input').prop('disabled', false).filter('input[rel="'+(mystatus || '')+'"]').prop('disabled', true);
 
         if (show_rsvp && event.comment)
           $('#event-rsvp-comment').show().find('.event-text').html(Q(event.comment));
 
         $('#event-rsvp a.reply-comment-toggle').show();
         $('#event-rsvp .itip-reply-comment textarea').hide().val('');
 
         if (event.recurrence && event.id) {
           var sel = event._savemode || (event.thisandfuture ? 'future' : (event.isexception ? 'current' : 'all'));
           $('#event-rsvp .rsvp-buttons').addClass('recurring');
         }
         else {
           $('#event-rsvp .rsvp-buttons').removeClass('recurring');
         }
       }
 
       var buttons = [];
       if (!temp && calendar.editable && event.editable !== false) {
         buttons.push({
           text: rcmail.gettext('edit', 'calendar'),
           'class': 'edit mainaction',
           click: function() {
             event_edit_dialog('edit', event);
           }
         });
       }
       if (!temp && me.has_permission(calendar, 'td') && event.editable !== false) {
         buttons.push({
           text: rcmail.gettext('delete', 'calendar'),
           'class': 'delete',
           click: function() {
             me.delete_event(event);
             $dialog.dialog('close');
           }
         });
       }
 
       buttons.push({
         text: rcmail.gettext('close', 'calendar'),
         'class': 'cancel',
         click: function() {
           $dialog.dialog('close');
         }
       });
 
       // open jquery UI dialog
       $dialog.dialog({
         modal: true,
         resizable: true,
         closeOnEscape: true,
         title: me.event_date_text(event),
         open: function() {
           $dialog.attr('aria-hidden', 'false');
           setTimeout(function(){
             $dialog.parent().find('.ui-button:not(.ui-dialog-titlebar-close)').first().focus();
           }, 5);
         },
         beforeClose: function(e) {
           rcmail.command('menu-close', 'eventoptionsmenu', null, e);
         },
         close: function(e) {
           $dialog.dialog('destroy').attr('aria-hidden', 'true').hide();
           $('.libcal-rsvp-replymode').hide();
         },
         dragStart: function(e) {
           rcmail.command('menu-close', 'eventoptionsmenu', null, e);
           $('.libcal-rsvp-replymode').hide();
         },
         resizeStart: function(e) {
           rcmail.command('menu-close', 'eventoptionsmenu', null, e);
           $('.libcal-rsvp-replymode').hide();
         },
         buttons: buttons,
         minWidth: 320,
         width: 420
       }).show();
 
       // remember opener element (to be focused on close)
       $dialog.data('opener', ev && rcube_event.is_keyboard(ev) ? ev.target : null);
 
       // set voice title on dialog widget
       $dialog.dialog('widget').removeAttr('aria-labelledby')
         .attr('aria-label', me.event_date_text(event, true) + ', ', event.title);
 
       // set dialog size according to content
       me.dialog_resize($dialog.get(0), $dialog.height(), 420);
 
       // add link for "more options" drop-down
       if (!temp && !event.temporary && event.calendar != '_resource') {
         $('<a>')
           .attr({href: '#', 'class': 'dropdown-link btn btn-link options', 'data-popup-pos': 'top'})
           .text(rcmail.gettext('eventoptions','calendar'))
           .click(function(e) {
             return rcmail.command('menu-open','eventoptionsmenu', this, e)
           })
           .appendTo($dialog.parent().find('.ui-dialog-buttonset'));
       }
 
       rcmail.enable_command('event-history', calendar.history)
 
       rcmail.triggerEvent('calendar-event-dialog', {dialog: $dialog});
     };
 
     // event handler for clicks on an attendee link
     var event_attendee_click = function(e)
     {
       var cutype = $(this).attr('data-cutype'),
         mailto = this.href.substr(7);
       if (rcmail.env.calendar_resources && cutype == 'RESOURCE') {
         event_resources_dialog(mailto);
       }
       else {
         rcmail.command('compose', mailto, e ? e.target : null, e);
       }
       return false;
     };
 
     // bring up the event dialog (jquery-ui popup)
     var event_edit_dialog = function(action, event)
     {
       // copy opener element from show dialog
       var op_elem = $("#eventshow:ui-dialog").data('opener');
 
       // close show dialog first
       $("#eventshow:ui-dialog").data('opener', null).dialog('close');
 
       var $dialog = $('<div>');
       var calendar = event.calendar && me.calendars[event.calendar] ? me.calendars[event.calendar] : { editable:true, rights: action=='new' ? 'lrwitd' : 'lrs' };
       me.selected_event = $.extend($.extend({}, event_defaults), event);  // clone event object (with defaults)
       event = me.selected_event; // change reference to clone
       freebusy_ui.needsupdate = false;
 
       if (rcmail.env.action == 'dialog-ui')
         calendar.attendees = false; // TODO: allow Attendees tab in Save-as-event dialog
 
       // reset dialog first
       $('#eventedit form').trigger('reset');
       $('#event-panel-recurrence input, #event-panel-recurrence select, #event-panel-attachments input').prop('disabled', false);
       $('#event-panel-recurrence, #event-panel-attachments').removeClass('disabled');
 
       // allow other plugins to do actions when event form is opened
       rcmail.triggerEvent('calendar-event-init', {o: event});
 
       // event details
       var title = $('#edit-title').val(event.title || '');
       var location = $('#edit-location').val(event.location || '');
       var description = $('#edit-description').text(event.description || '');
       var vurl = $('#edit-url').val(event.vurl || '');
       var categories = $('#edit-categories').val(event.categories);
       var calendars = $('#edit-calendar').val(event.calendar);
       var eventstatus = $('#edit-event-status').val(event.status);
       var freebusy = $('#edit-free-busy').val(event.free_busy);
       var priority = $('#edit-priority').val(event.priority);
       var sensitivity = $('#edit-sensitivity').val(event.sensitivity);
       var syncstart = $('#edit-recurrence-syncstart input');
       var end = 'toDate' in event.end ? event.end : moment(event.end);
       var start = 'toDate' in event.start ? event.start : moment(event.start);
       var duration = Math.round((end.format('x') - start.format('x')) / 1000);
 
       // Correct the fullCalendar end date for all-day events
       if (!end.hasTime()) {
         end.subtract(1, 'days');
       }
 
       var startdate = $('#edit-startdate').val(format_date(start, settings.date_format)).data('duration', duration);
       var starttime = $('#edit-starttime').val(format_date(start, settings.time_format)).show();
       var enddate = $('#edit-enddate').val(format_date(end, settings.date_format));
       var endtime = $('#edit-endtime').val(format_date(end, settings.time_format)).show();
       var allday = $('#edit-allday').get(0);
       var notify = $('#edit-attendees-donotify').get(0);
       var invite = $('#edit-attendees-invite').get(0);
       var comment = $('#edit-attendees-comment');
 
       // make sure any calendar is selected
       if (!calendars.val())
         calendars.val($('option:first', calendars).attr('value'));
 
       invite.checked = settings.itip_notify & 1 > 0;
       notify.checked = me.has_attendees(event) && invite.checked;
 
       if (event.allDay) {
         starttime.val("12:00").hide();
         endtime.val("13:00").hide();
         allday.checked = true;
       }
       else {
         allday.checked = false;
       }
 
       // set calendar selection according to permissions
       calendars.find('option').each(function(i, opt) {
         var cal = me.calendars[opt.value] || {};
         $(opt).prop('disabled', !(cal.editable || (action == 'new' && me.has_permission(cal, 'i'))))
       });
 
       // set alarm(s)
       me.set_alarms_edit('#edit-alarms', action != 'new' && event.valarms && calendar.alarms ? event.valarms : []);
 
       // enable/disable alarm property according to backend support
       $('#edit-alarms')[(calendar.alarms ? 'show' : 'hide')]();
 
       // check categories drop-down: add value if not exists
       if (event.categories && !categories.find("option[value='"+event.categories+"']").length) {
         $('<option>').attr('value', event.categories).text(event.categories).appendTo(categories).prop('selected', true);
       }
 
       if ($.isArray(event.links) && event.links.length) {
           render_message_links(event.links, $('#edit-event-links .event-text'), true, 'calendar');
           $('#edit-event-links').show();
       }
       else {
           $('#edit-event-links').hide();
       }
 
       // show warning if editing a recurring event
       if (event.id && event.recurrence) {
         var sel = event._savemode || (event.thisandfuture ? 'future' : (event.isexception ? 'current' : 'all'));
         $('#edit-recurring-warning').show();
         $('input.edit-recurring-savemode[value="'+sel+'"]').prop('checked', true).change();
       }
       else
         $('#edit-recurring-warning').hide();
 
       // init attendees tab
       var organizer = !event.attendees || me.is_organizer(event),
         allow_invitations = organizer || (calendar.owner && calendar.owner == 'anonymous') || settings.invite_shared;
       event_attendees = [];
       attendees_list = $('#edit-attendees-table > tbody').html('');
       resources_list = $('#edit-resources-table > tbody').html('');
       $('#edit-attendees-notify')[(action != 'new' && allow_invitations && me.has_attendees(event) && (settings.itip_notify & 2) ? 'show' : 'hide')]();
       $('#edit-localchanges-warning')[(action != 'new' && me.has_attendees(event) && !(allow_invitations || (calendar.owner && me.is_organizer(event, calendar.owner))) ? 'show' : 'hide')]();
 
       var load_attendees_tab = function()
       {
         var j, data, organizer_attendee, reply_selected = 0;
         if (event.attendees) {
           for (j=0; j < event.attendees.length; j++) {
             data = event.attendees[j];
             // reset attendee status
             if (event._savemode == 'new' && data.role != 'ORGANIZER') {
               data.status = 'NEEDS-ACTION';
               delete data.noreply;
             }
             add_attendee(data, !allow_invitations);
             if (allow_invitations && data.role != 'ORGANIZER' && !data.noreply)
               reply_selected++;
 
             if (data.role == 'ORGANIZER')
               organizer_attendee = data;
           }
         }
 
         // make sure comment box is visible if at least one attendee has reply enabled
         // or global "send invitations" checkbox is checked
         $('#eventedit .attendees-commentbox')[(reply_selected || invite.checked ? 'show' : 'hide')]();
 
         // select the correct organizer identity
         var identity_id = 0;
         $.each(settings.identities, function(i,v){
           if (organizer && typeof organizer == 'object' && v == organizer.email) {
             identity_id = i;
             return false;
           }
         });
 
         // In case the user is not the (shared) event organizer we'll add the organizer to the selection list
         if (!identity_id && !organizer && organizer_attendee) {
           var organizer_name = organizer_attendee.email;
           if (organizer_attendee.name)
             organizer_name = '"' + organizer_attendee.name + '" <' + organizer_name + '>';
           $('#edit-identities-list').append($('<option value="0">').text(organizer_name));
         }
 
         $('#edit-identities-list').val(identity_id);
         $('#edit-attendees-form')[(allow_invitations?'show':'hide')]();
         $('#edit-attendee-schedule')[(calendar.freebusy?'show':'hide')]();
       };
 
       // attachments
       var load_attachments_tab = function()
       {
         rcmail.enable_command('remove-attachment', 'upload-file', calendar.editable && !event.recurrence_id);
         rcmail.env.deleted_attachments = [];
         // we're sharing some code for uploads handling with app.js
         rcmail.env.attachments = [];
         rcmail.env.compose_id = event.id; // for rcmail.async_upload_form()
 
         if ($.isArray(event.attachments)) {
           event_show_attachments(event.attachments, $('#edit-attachments'), event, true);
         }
         else {
           $('#edit-attachments > ul').empty();
           // fetch attachments, some drivers doesn't set 'attachments' array for event?
         }
       };
 
       // init dialog buttons
       var buttons = [],
         save_func = function() {
-          var start = me.parse_datetime(allday.checked ? '12:00' : starttime.val(), startdate.val());
-          var end   = me.parse_datetime(allday.checked ? '13:00' : endtime.val(), enddate.val());
+          var start = allday.checked ? '12:00' : $.trim(starttime.val()),
+            end = allday.checked ? '13:00' : $.trim(endtime.val()),
+            re = /^((0[0-9])|(1[0-9])|(2[0-3])):([0-5][0-9])(\s*[ap]\.?m\.?)?$/i;
+
+          if (!re.test(start) || !re.test(end)) {
+            rcmail.alert_dialog(rcmail.gettext('invalideventdates', 'calendar'));
+            return false;
+          }
+
+          start = me.parse_datetime(start, startdate.val());
+          end   = me.parse_datetime(end, enddate.val());
 
-          // basic input validation
           if (!title.val()) {
             rcmail.alert_dialog(rcmail.gettext('emptyeventtitle', 'calendar'));
             return false;
           }
 
           if (start.getTime() > end.getTime()) {
             rcmail.alert_dialog(rcmail.gettext('invalideventdates', 'calendar'));
             return false;
           }
 
           // post data to server
           var data = {
             calendar: event.calendar,
             start: date2servertime(start),
             end: date2servertime(end),
             allDay: allday.checked?1:0,
             title: title.val(),
             description: description.val(),
             location: location.val(),
             categories: categories.val(),
             vurl: vurl.val(),
             free_busy: freebusy.val(),
             priority: priority.val(),
             sensitivity: sensitivity.val(),
             status: eventstatus.val(),
             recurrence: me.serialize_recurrence(endtime.val()),
             valarms: me.serialize_alarms('#edit-alarms'),
             attendees: event_attendees,
             links: me.selected_event.links,
             deleted_attachments: rcmail.env.deleted_attachments,
             attachments: []
           };
 
           // uploaded attachments list
           for (var i in rcmail.env.attachments)
             if (i.match(/^rcmfile(.+)/))
               data.attachments.push(RegExp.$1);
 
           // read attendee roles
           $('select.edit-attendee-role').each(function(i, elem){
             if (data.attendees[i])
               data.attendees[i].role = $(elem).val();
           });
 
           if (organizer)
             data._identity = $('#edit-identities-list option:selected').val();
 
           // per-attendee notification suppression
           var need_invitation = false;
           if (allow_invitations) {
             $.each(data.attendees, function (i, v) {
               if (v.role != 'ORGANIZER') {
                 if ($('input.edit-attendee-reply[value="' + v.email + '"]').prop('checked') || v.cutype == 'RESOURCE') {
                   need_invitation = true;
                   delete data.attendees[i]['noreply'];
                 }
                 else if (settings.itip_notify > 0) {
                   data.attendees[i].noreply = 1;
                 }
               }
             });
           }
 
           // tell server to send notifications
           if ((data.attendees.length || (event.id && event.attendees.length)) && allow_invitations && (notify.checked || invite.checked || need_invitation)) {
             data._notify = settings.itip_notify;
             data._comment = comment.val();
           }
 
           data.calendar = calendars.val();
 
           if (event.id) {
             data.id = event.id;
             if (event.recurrence)
               data._savemode = $('input.edit-recurring-savemode:checked').val();
             if (data.calendar && data.calendar != event.calendar)
               data._fromcalendar = event.calendar;
           }
 
           if (data.recurrence && syncstart.is(':checked'))
             data.syncstart = 1;
 
           update_event(action, data);
 
           if (rcmail.env.action != 'dialog-ui')
             $dialog.dialog("close");
         };
 
       rcmail.env.event_save_func = save_func;
 
       // save action
       buttons.push({
         text: rcmail.gettext('save', 'calendar'),
         'class': 'save mainaction',
         click: save_func
       });
 
       buttons.push({
         text: rcmail.gettext('cancel', 'calendar'),
         'class': 'cancel',
         click: function() {
           $dialog.dialog("close");
         }
       });
 
       // show/hide tabs according to calendar's feature support and activate first tab (Larry)
       $('#edit-tab-attendees')[(calendar.attendees?'show':'hide')]();
       $('#edit-tab-resources')[(rcmail.env.calendar_resources?'show':'hide')]();
       $('#edit-tab-attachments')[(calendar.attachments?'show':'hide')]();
       $('#eventedit:not([data-notabs])').tabs('option', 'active', 0); // Larry
 
       // show/hide tabs according to calendar's feature support and activate first tab (Ellastic)
       $('li > a[href="#event-panel-attendees"]').parent()[(calendar.attendees?'show':'hide')]();
       $('li > a[href="#event-panel-resources"]').parent()[(rcmail.env.calendar_resources?'show':'hide')]();
       $('li > a[href="#event-panel-attachments"]').parent()[(calendar.attachments?'show':'hide')]();
       if ($('#eventedit').data('notabs'))
         $('#eventedit li.nav-item:first-child a').tab('show');
 
       // hack: set task to 'calendar' to make all dialog actions work correctly
       var comm_path_before = rcmail.env.comm_path;
       rcmail.env.comm_path = comm_path_before.replace(/_task=[a-z]+/, '_task=calendar');
 
       var editform = $("#eventedit");
 
       if (rcmail.env.action != 'dialog-ui') {
         // open jquery UI dialog
         $dialog.dialog({
           modal: true,
           resizable: true,
           closeOnEscape: false,
           title: rcmail.gettext((action == 'edit' ? 'edit_event' : 'new_event'), 'calendar'),
           open: function() {
             editform.attr('aria-hidden', 'false');
           },
           close: function() {
             editform.hide().attr('aria-hidden', 'true').appendTo(document.body);
             $dialog.dialog("destroy").remove();
             rcmail.ksearch_blur();
             freebusy_data = {};
             rcmail.env.comm_path = comm_path_before;  // restore comm_path
             if (op_elem)
               $(op_elem).focus();
           },
           buttons: buttons,
           minWidth: 500,
           width: 600
         }).append(editform.show());  // adding form content AFTERWARDS massively speeds up opening on IE6
 
         // set dialog size according to form content
         me.dialog_resize($dialog.get(0), editform.height() + (bw.ie ? 20 : 0), 550);
 
         rcmail.triggerEvent('calendar-event-dialog', {dialog: $dialog});
       }
 
       // init other tabs asynchronously
       window.setTimeout(function(){ me.set_recurrence_edit(event); }, exec_deferred);
       if (calendar.attendees)
         window.setTimeout(load_attendees_tab, exec_deferred);
       if (calendar.attachments)
         window.setTimeout(load_attachments_tab, exec_deferred);
 
       title.select();
     };
 
     // show event changelog in a dialog
     var event_history_dialog = function(event)
     {
       if (!event.id || !window.libkolab_audittrail)
         return false
 
       // render dialog
       var $dialog = libkolab_audittrail.object_history_dialog({
         module: 'calendar',
         container: '#eventhistory',
         title: rcmail.gettext('objectchangelog','calendar') + ' - ' + event.title + ', ' + me.event_date_text(event),
 
         // callback function for list actions
         listfunc: function(action, rev) {
           me.loading_lock = rcmail.set_busy(true, 'loading', me.loading_lock);
           rcmail.http_post('event', { action:action, e:{ id:event.id, calendar:event.calendar, rev: rev } }, me.loading_lock);
         },
 
         // callback function for comparing two object revisions
         comparefunc: function(rev1, rev2) {
           me.loading_lock = rcmail.set_busy(true, 'loading', me.loading_lock);
           rcmail.http_post('event', { action:'diff', e:{ id:event.id, calendar:event.calendar, rev1: rev1, rev2: rev2 } }, me.loading_lock);
         }
       });
 
       $dialog.data('event', event);
 
       // fetch changelog data
       me.loading_lock = rcmail.set_busy(true, 'loading', me.loading_lock);
       rcmail.http_post('event', { action:'changelog', e:{ id:event.id, calendar:event.calendar } }, me.loading_lock);
     };
 
     // callback from server with changelog data
     var render_event_changelog = function(data)
     {
       var $dialog = $('#eventhistory'),
         event = $dialog.data('event');
 
       if (data === false || !data.length || !event) {
         // display 'unavailable' message
         $('<div class="notfound-message dialog-message warning">' + rcmail.gettext('objectchangelognotavailable','calendar') + '</div>')
           .insertBefore($dialog.find('.changelog-table').hide());
         return;
       }
 
       data.module = 'calendar';
       libkolab_audittrail.render_changelog(data, event, me.calendars[event.calendar]);
 
       // set dialog size according to content
       me.dialog_resize($dialog.get(0), $dialog.height(), 600);
     };
 
     // callback from server with event diff data
     var event_show_diff = function(data)
     {
       var event = me.selected_event,
         $dialog = $("#eventdiff");
 
       $dialog.find('div.event-section, div.event-line, h1.event-title-new').hide().data('set', false).find('.index').html('');
       $dialog.find('div.event-section.clone, div.event-line.clone').remove();
 
       // always show event title and date
       $('.event-title', $dialog).text(event.title).removeClass('event-text-old').show();
       $('.event-date', $dialog).text(me.event_date_text(event)).show();
 
       // show each property change
       $.each(data.changes, function(i,change) {
         var prop = change.property, r2, html = false,
           row = $('div.event-' + prop, $dialog).first();
 
           // special case: title
           if (prop == 'title') {
             $('.event-title', $dialog).addClass('event-text-old').text(change['old'] || '--');
             $('.event-title-new', $dialog).text(change['new'] || '--').show();
           }
 
           // no display container for this property
           if (!row.length) {
             return true;
           }
 
           // clone row if already exists
           if (row.data('set')) {
             r2 = row.clone().addClass('clone').insertAfter(row);
             row = r2;
           }
 
           // format dates
           if (['start','end','changed'].indexOf(prop) >= 0) {
             if (change['old']) change.old_ = me.format_datetime(parseISO8601(change['old']));
             if (change['new']) change.new_ = me.format_datetime(parseISO8601(change['new']));
           }
           // render description text
           else if (prop == 'description') {
             // TODO: show real text diff
             if (!change.diff_ && change['old']) change.old_ = text2html(change['old']);
             if (!change.diff_ && change['new']) change.new_ = text2html(change['new']);
             html = true;
           }
           // format attendees struct
           else if (prop == 'attendees') {
             if (change['old']) change.old_ = rcube_libcalendaring.attendee_html(change['old']);
             if (change['new']) change.new_ = rcube_libcalendaring.attendee_html($.extend({}, change['old'] || {}, change['new']));
             html = true;
           }
           // localize priority values
           else if (prop == 'priority') {
             var priolabels = [ '', rcmail.gettext('highest'), rcmail.gettext('high'), '', '', rcmail.gettext('normal'), '', '', rcmail.gettext('low'), rcmail.gettext('lowest') ];
             if (change['old']) change.old_ = change['old'] + ' ' + (priolabels[change['old']] || '');
             if (change['new']) change.new_ = change['new'] + ' ' + (priolabels[change['new']] || '');
           }
           // localize status
           else if (prop == 'status') {
             var status_lc = String(event.status).toLowerCase();
             if (change['old']) change.old_ = rcmail.gettext(String(change['old']).toLowerCase(), 'calendar');
             if (change['new']) change.new_ = rcmail.gettext(String(change['new']).toLowerCase(), 'calendar');
           }
 
           // format attachments struct
           if (prop == 'attachments') {
             if (change['old']) event_show_attachments([change['old']], row.children('.event-text-old'), event, false);
             else            row.children('.event-text-old').text('--');
             if (change['new']) event_show_attachments([$.extend({}, change['old'] || {}, change['new'])], row.children('.event-text-new'), event, false);
             else            row.children('.event-text-new').text('--');
             // remove click handler as we're currentyl not able to display the according attachment contents
             $('.attachmentslist li a', row).unbind('click').removeAttr('href');
           }
           else if (change.diff_) {
             row.children('.event-text-diff').html(change.diff_);
             row.children('.event-text-old, .event-text-new').hide();
           }
           else {
             if (!html) {
               // escape HTML characters
               change.old_ = Q(change.old_ || change['old'] || '--')
               change.new_ = Q(change.new_ || change['new'] || '--')
             }
             row.children('.event-text-old').html(change.old_ || change['old'] || '--');
             row.children('.event-text-new').html(change.new_ || change['new'] || '--');
           }
 
           // display index number
           if (typeof change.index != 'undefined') {
             row.find('.index').html('(' + change.index + ')');
           }
 
           row.show().data('set', true);
 
           // hide event-date line
           if (prop == 'start' || prop == 'end')
             $('.event-date', $dialog).hide();
       });
 
       var buttons = [{
         text: rcmail.gettext('close', 'calendar'),
         'class': 'cancel',
         click: function() { $dialog.dialog('close'); }
       }];
 
       // open jquery UI dialog
       $dialog.dialog({
         modal: false,
         resizable: true,
         closeOnEscape: true,
         title: rcmail.gettext('objectdiff','calendar').replace('$rev1', data.rev1).replace('$rev2', data.rev2) + ' - ' + event.title,
         open: function() {
           $dialog.attr('aria-hidden', 'false');
           setTimeout(function(){
             $dialog.parent().find('.ui-button:not(.ui-dialog-titlebar-close)').first().focus();
           }, 5);
         },
         close: function() {
           $dialog.dialog('destroy').attr('aria-hidden', 'true').hide();
         },
         buttons: buttons,
         minWidth: 320,
         width: 450
       }).show();
 
       // set dialog size according to content
       me.dialog_resize($dialog.get(0), $dialog.height(), 400);
     };
 
     // close the event history dialog
     var close_history_dialog = function()
     {
       $('#eventhistory, #eventdiff').each(function(i, elem) {
         var $dialog = $(elem);
         if ($dialog.is(':ui-dialog'))
           $dialog.dialog('close');
       });
     }
 
     // exports
     this.event_show_diff = event_show_diff;
     this.event_show_dialog = event_show_dialog;
     this.event_history_dialog = event_history_dialog;
     this.render_event_changelog = render_event_changelog;
     this.close_history_dialog = close_history_dialog;
 
     // open a dialog to display detailed free-busy information and to find free slots
     var event_freebusy_dialog = function()
     {
       var $dialog = $('#eventfreebusy'),
         event = me.selected_event;
       
       if ($dialog.is(':ui-dialog'))
         $dialog.dialog('close');
       
       if (!event_attendees.length)
         return false;
       
       // set form elements
       var allday = $('#edit-allday').get(0);
       var end = 'toDate' in event.end ? event.end : moment(event.end);
       var start = 'toDate' in event.start ? event.start : moment(event.start);
       var duration = Math.round((end.format('x') - start.format('x')) / 1000);
 
       freebusy_ui.startdate = $('#schedule-startdate').val(format_date(start, settings.date_format)).data('duration', duration);
       freebusy_ui.starttime = $('#schedule-starttime').val(format_date(start, settings.time_format)).show();
       freebusy_ui.enddate = $('#schedule-enddate').val(format_date(end, settings.date_format));
       freebusy_ui.endtime = $('#schedule-endtime').val(format_date(end, settings.time_format)).show();
       
       if (allday.checked) {
         freebusy_ui.starttime.val("12:00").hide();
         freebusy_ui.endtime.val("13:00").hide();
         event.allDay = true;
       }
       
       // read attendee roles from drop-downs
       $('select.edit-attendee-role').each(function(i, elem){
         if (event_attendees[i])
           event_attendees[i].role = $(elem).val();
       });
       
       // render time slots
       var now = new Date(), fb_start = new Date(), fb_end = new Date();
       fb_start.setTime(event.start);
       fb_start.setHours(0); fb_start.setMinutes(0); fb_start.setSeconds(0); fb_start.setMilliseconds(0);
       fb_end.setTime(fb_start.getTime() + DAY_MS);
       
       freebusy_data = { required:{}, all:{} };
       freebusy_ui.loading = 1;  // prevent render_freebusy_grid() to load data yet
       freebusy_ui.numdays = Math.max(allday.checked ? 14 : 1, Math.ceil(duration * 2 / 86400));
       freebusy_ui.interval = allday.checked ? 1440 : (60 / (settings.timeslots || 1));
       freebusy_ui.start = fb_start;
       freebusy_ui.end = new Date(freebusy_ui.start.getTime() + DAY_MS * freebusy_ui.numdays);
       render_freebusy_grid(0);
       
       // render list of attendees
       freebusy_ui.attendees = {};
       var domid, dispname, data, role_html, list_html = '';
       for (var i=0; i < event_attendees.length; i++) {
         data = event_attendees[i];
         dispname = Q(data.name || data.email);
         domid = String(data.email).replace(rcmail.identifier_expr, '');
         role_html = '<a class="attendee-role-toggle" id="rcmlia' + domid + '" title="' + Q(rcmail.gettext('togglerole', 'calendar')) + '">&nbsp;</a>';
         list_html += '<div class="attendee ' + String(data.role).toLowerCase() + '" id="rcmli' + domid + '">' + role_html + dispname + '</div>';
         
         // clone attendees data for local modifications
         freebusy_ui.attendees[i] = freebusy_ui.attendees[domid] = $.extend({}, data);
       }
       
       // add total row
       list_html += '<div class="attendee spacer">&nbsp;</div>';
       list_html += '<div class="attendee total">' + rcmail.gettext('reqallattendees','calendar') + '</div>';
       
       $('#schedule-attendees-list').html(list_html)
         .unbind('click.roleicons')
         .bind('click.roleicons', function(e){
           // toggle attendee status upon click on icon
           if (e.target.id && e.target.id.match(/rcmlia(.+)/)) {
             var attendee, domid = RegExp.$1,
                 roles = [ 'REQ-PARTICIPANT', 'OPT-PARTICIPANT', 'NON-PARTICIPANT', 'CHAIR' ];
             if ((attendee = freebusy_ui.attendees[domid]) && attendee.role != 'ORGANIZER') {
               var req = attendee.role != 'OPT-PARTICIPANT' && attendee.role != 'NON-PARTICIPANT';
               var j = $.inArray(attendee.role, roles);
               j = (j+1) % roles.length;
               attendee.role = roles[j];
               $(e.target).parent().attr('class', 'attendee '+String(attendee.role).toLowerCase());
               
               // update total display if required-status changed
               if (req != (roles[j] != 'OPT-PARTICIPANT' && roles[j] != 'NON-PARTICIPANT')) {
                 compute_freebusy_totals();
                 update_freebusy_display(attendee.email);
               }
             }
           }
           
           return false;
         });
       
       // enable/disable buttons
       // FIXME: .button() does nothing in Elastic skin
       var disabled = fb_start.getTime() < now.getTime();
       $('#schedule-find-prev').button('option', 'disabled', disabled).prop('disabled', disabled);
       
       // dialog buttons
       var buttons = [
         {
           text: rcmail.gettext('select', 'calendar'),
           'class': 'save mainaction',
           click: function() {
             $('#edit-startdate').val(freebusy_ui.startdate.val());
             $('#edit-starttime').val(freebusy_ui.starttime.val());
             $('#edit-enddate').val(freebusy_ui.enddate.val());
             $('#edit-endtime').val(freebusy_ui.endtime.val());
 
             // write role changes back to main dialog
             $('select.edit-attendee-role').each(function(i, elem){
               if (event_attendees[i] && freebusy_ui.attendees[i]) {
                 event_attendees[i].role = freebusy_ui.attendees[i].role;
                 $(elem).val(event_attendees[i].role);
               }
             });
 
             if (freebusy_ui.needsupdate)
               update_freebusy_status(me.selected_event);
             freebusy_ui.needsupdate = false;
             $dialog.dialog("close");
           }
         },
         {
           text: rcmail.gettext('cancel', 'calendar'),
           'class': 'cancel',
           click: function() { $dialog.dialog("close"); }
         }
       ];
 
       $dialog.dialog({
         modal: true,
         resizable: true,
         closeOnEscape: true,
         title: rcmail.gettext('scheduletime', 'calendar'),
         open: function() {
           rcmail.ksearch_blur();
           $dialog.attr('aria-hidden', 'false').find('#schedule-find-next, #schedule-find-prev').not(':disabled').first().focus();
         },
         close: function() {
           $dialog.dialog("destroy").attr('aria-hidden', 'true').hide();
           // TODO: focus opener button
         },
         resizeStop: function() {
           render_freebusy_overlay();
         },
         buttons: buttons,
         minWidth: 640,
         width: 850
       }).show();
       
       // adjust dialog size to fit grid without scrolling
       var gridw = $('#schedule-freebusy-times').width();
       var overflow = gridw - $('#attendees-freebusy-table td.times').width();
       me.dialog_resize($dialog.get(0), $dialog.height() + (bw.ie ? 20 : 0), 800 + Math.max(0, overflow));
       
       // fetch data from server
       freebusy_ui.loading = 0;
       load_freebusy_data(freebusy_ui.start, freebusy_ui.interval);
     };
 
     // render an HTML table showing free-busy status for all the event attendees
     var render_freebusy_grid = function(delta)
     {
       if (delta) {
         freebusy_ui.start.setTime(freebusy_ui.start.getTime() + DAY_MS * delta);
         fix_date(freebusy_ui.start);
         
         // skip weekends if in workinhoursonly-mode
         if (Math.abs(delta) == 1 && freebusy_ui.workinhoursonly) {
           while (is_weekend(freebusy_ui.start))
             freebusy_ui.start.setTime(freebusy_ui.start.getTime() + DAY_MS * delta);
           fix_date(freebusy_ui.start);
         }
         
         freebusy_ui.end = new Date(freebusy_ui.start.getTime() + DAY_MS * freebusy_ui.numdays);
       }
       
       var dayslots = Math.floor(1440 / freebusy_ui.interval);
       var date_format = 'ddd '+ (dayslots <= 2 ? settings.date_short : settings.date_format);
       var lastdate, datestr, css,
         curdate = new Date(),
         allday = (freebusy_ui.interval == 1440),
         interval = allday ? 1440 : (freebusy_ui.interval * (settings.timeslots || 1));
         times_css = (allday ? 'allday ' : ''),
         dates_row = '<tr class="dates">',
         times_row = '<tr class="times">',
         slots_row = '';
 
       for (var s = 0, t = freebusy_ui.start.getTime(); t < freebusy_ui.end.getTime(); s++) {
         curdate.setTime(t);
         datestr = format_date(curdate, date_format);
         if (datestr != lastdate) {
           if (lastdate && !allday) break;
           dates_row += '<th colspan="' + dayslots + '" class="boxtitle date' + format_date(curdate, 'DDMMYYYY') + '">' + Q(datestr) + '</th>';
           lastdate = datestr;
         }
         
         // set css class according to working hours
         css = is_weekend(curdate) || (freebusy_ui.interval <= 60 && !is_workinghour(curdate)) ? 'offhours' : 'workinghours';
         times_row += '<td class="' + times_css + css + '" id="t-' + Math.floor(t/1000) + '">' + Q(allday ? rcmail.gettext('all-day','calendar') : format_date(curdate, settings.time_format)) + '</td>';
         slots_row += '<td class="' + css + '">&nbsp;</td>';
         
         t += interval * 60000;
       }
       dates_row += '</tr>';
       times_row += '</tr>';
       
       // render list of attendees
       var domid, data, list_html = '', times_html = '';
       for (var i=0; i < event_attendees.length; i++) {
         data = event_attendees[i];
         domid = String(data.email).replace(rcmail.identifier_expr, '');
         times_html += '<tr id="fbrow' + domid + '" class="fbcontent">' + slots_row + '</tr>';
       }
       
       // add line for all/required attendees
       times_html += '<tr class="spacer"><td colspan="' + (dayslots * freebusy_ui.numdays) + '"></td>';
       times_html += '<tr id="fbrowall" class="fbcontent">' + slots_row + '</tr>';
       
       var table = $('#schedule-freebusy-times');
       table.children('thead').html(dates_row + times_row);
       table.children('tbody').html(times_html);
       
       // initialize event handlers on grid
       if (!freebusy_ui.grid_events) {
         freebusy_ui.grid_events = true;
         table.children('thead').click(function(e){
           // move event to the clicked date/time
           if (e.target.id && e.target.id.match(/t-(\d+)/)) {
             var newstart = new Date(RegExp.$1 * 1000);
             // set time to 00:00
             if (me.selected_event.allDay) {
               newstart.setMinutes(0);
               newstart.setHours(0);
             }
             update_freebusy_dates(newstart, new Date(newstart.getTime() + freebusy_ui.startdate.data('duration') * 1000));
             render_freebusy_overlay();
           }
         });
       }
       
       // if we have loaded free-busy data, show it
       if (!freebusy_ui.loading) {
         if (freebusy_ui.start < freebusy_data.start || freebusy_ui.end > freebusy_data.end || freebusy_ui.interval != freebusy_data.interval) {
           load_freebusy_data(freebusy_ui.start, freebusy_ui.interval);
         }
         else {
           for (var email, i=0; i < event_attendees.length; i++) {
             if ((email = event_attendees[i].email))
               update_freebusy_display(email);
           }
         }
       }
       
       // render current event date/time selection over grid table
       // use timeout to let the dom attributes (width/height/offset) be set first
       window.setTimeout(function(){ render_freebusy_overlay(); }, 10);
     };
     
     // render overlay element over the grid to visiualize the current event date/time
     var render_freebusy_overlay = function()
     {
       var overlay = $('#schedule-event-time');
       if (me.selected_event.end.getTime() <= freebusy_ui.start.getTime() || me.selected_event.start.getTime() >= freebusy_ui.end.getTime()) {
         overlay.hide();
         if (overlay.data('isdraggable'))
           overlay.draggable('disable');
       }
       else {
         var i, n, table = $('#schedule-freebusy-times'),
           width = 0,
           pos = { top:table.children('thead').height(), left:0 },
           eventstart = date2unixtime(clone_date(me.selected_event.start, me.selected_event.allDay?1:0)),
           eventend = date2unixtime(clone_date(me.selected_event.end, me.selected_event.allDay?2:0)) - 60,
           slotstart = date2unixtime(freebusy_ui.start),
           slotsize = freebusy_ui.interval * 60,
           slotnum = freebusy_ui.interval > 60 ? 1 : (60 / freebusy_ui.interval),
           cells = table.children('thead').find('td'),
           cell_width = cells.first().get(0).offsetWidth,
           h_margin = table.parents('table').data('h-margin'),
           v_margin = table.parents('table').data('v-margin'),
           slotend;
 
         if (h_margin === undefined)
           h_margin = 4;
         if (v_margin === undefined)
           v_margin = 4;
 
         // iterate through slots to determine position and size of the overlay
         for (i=0; i < cells.length; i++) {
           for (n=0; n < slotnum; n++) {
             slotend = slotstart + slotsize - 1;
             // event starts in this slot: compute left
             if (eventstart >= slotstart && eventstart <= slotend) {
               pos.left = Math.round(i * cell_width + (cell_width / slotnum) * n);
             }
             // event ends in this slot: compute width
             if (eventend >= slotstart && eventend <= slotend) {
               width = Math.round(i * cell_width + (cell_width / slotnum) * (n + 1)) - pos.left;
             }
             slotstart += slotsize;
           }
         }
 
         if (!width)
           width = table.width() - pos.left;
 
         // overlay is visible
         if (width > 0) {
           overlay.css({
             width: (width - h_margin) + 'px',
             height: (table.children('tbody').height() - v_margin) + 'px',
             left: pos.left + 'px',
             top: pos.top + 'px'
           }).show();
 
           // configure draggable
           if (!overlay.data('isdraggable')) {
             overlay.draggable({
               axis: 'x',
               scroll: true,
               stop: function(e, ui){
                 // convert pixels to time
                 var px = ui.position.left;
                 var range_p = $('#schedule-freebusy-times').width();
                 var range_t = freebusy_ui.end.getTime() - freebusy_ui.start.getTime();
                 var newstart = new Date(freebusy_ui.start.getTime() + px * (range_t / range_p));
                 newstart.setSeconds(0); newstart.setMilliseconds(0);
                 // snap to day boundaries
                 if (me.selected_event.allDay) {
                   if (newstart.getHours() >= 12)  // snap to next day
                     newstart.setTime(newstart.getTime() + DAY_MS);
                   newstart.setMinutes(0);
                   newstart.setHours(0);
                 }
                 else {
                   // round to 5 minutes
                   // @TODO: round to timeslots?
                   var round = newstart.getMinutes() % 5;
                   if (round > 2.5) newstart.setTime(newstart.getTime() + (5 - round) * 60000);
                   else if (round > 0) newstart.setTime(newstart.getTime() - round * 60000);
                 }
                 // update event times and display
                 update_freebusy_dates(newstart, new Date(newstart.getTime() + freebusy_ui.startdate.data('duration') * 1000));
                 if (me.selected_event.allDay)
                   render_freebusy_overlay();
               }
             }).data('isdraggable', true);
           }
           else
             overlay.draggable('enable');
         }
         else
           overlay.draggable('disable').hide();
       }
     };
 
     // fetch free-busy information for each attendee from server
     var load_freebusy_data = function(from, interval)
     {
       var start = new Date(from.getTime() - DAY_MS * 2);  // start 2 days before event
       fix_date(start);
       var end = new Date(start.getTime() + DAY_MS * Math.max(14, freebusy_ui.numdays + 7));   // load min. 14 days
       freebusy_ui.numrequired = 0;
       freebusy_data.all = [];
       freebusy_data.required = [];
 
       // load free-busy information for every attendee
       var domid, email;
       for (var i=0; i < event_attendees.length; i++) {
         if ((email = event_attendees[i].email)) {
           domid = String(email).replace(rcmail.identifier_expr, '');
           $('#rcmli' + domid).addClass('loading');
           freebusy_ui.loading++;
           
           $.ajax({
             type: 'GET',
             dataType: 'json',
             url: rcmail.url('freebusy-times'),
             data: { email:email, start:date2servertime(clone_date(start, 1)), end:date2servertime(clone_date(end, 2)), interval:interval, _remote:1 },
             success: function(data) {
               freebusy_ui.loading--;
               
               // find attendee
               var i, attendee = null;
               for (i=0; i < event_attendees.length; i++) {
                 if (freebusy_ui.attendees[i].email == data.email) {
                   attendee = freebusy_ui.attendees[i];
                   break;
                 }
               }
               
               // copy data to member var
               var ts, status,
                 req = attendee.role != 'OPT-PARTICIPANT',
                 start = parseISO8601(data.start);
 
               freebusy_data.start = new Date(start);
               freebusy_data.end = parseISO8601(data.end);
               freebusy_data.interval = data.interval;
               freebusy_data[data.email] = {};
 
               for (i=0; i < data.slots.length; i++) {
                 ts = date2timestring(start, data.interval > 60);
                 status = data.slots.charAt(i);
                 freebusy_data[data.email][ts] = status
                 start = new Date(start.getTime() + data.interval * 60000);
                 
                 // set totals
                 if (!freebusy_data.required[ts])
                   freebusy_data.required[ts] = [0,0,0,0];
                 if (req)
                   freebusy_data.required[ts][status]++;
                 
                 if (!freebusy_data.all[ts])
                   freebusy_data.all[ts] = [0,0,0,0];
                 freebusy_data.all[ts][status]++;
               }
 
               // hide loading indicator
               var domid = String(data.email).replace(rcmail.identifier_expr, '');
               $('#rcmli' + domid).removeClass('loading');
               
               // update display
               update_freebusy_display(data.email);
             }
           });
           
           // count required attendees
           if (freebusy_ui.attendees[i].role != 'OPT-PARTICIPANT')
             freebusy_ui.numrequired++;
         }
       }
     };
     
     // re-calculate total status after role change
     var compute_freebusy_totals = function()
     {
       freebusy_ui.numrequired = 0;
       freebusy_data.all = [];
       freebusy_data.required = [];
       
       var email, req, status;
       for (var i=0; i < event_attendees.length; i++) {
         if (!(email = event_attendees[i].email))
           continue;
         
         req = freebusy_ui.attendees[i].role != 'OPT-PARTICIPANT';
         if (req)
           freebusy_ui.numrequired++;
         
         for (var ts in freebusy_data[email]) {
           if (!freebusy_data.required[ts])
             freebusy_data.required[ts] = [0,0,0,0];
           if (!freebusy_data.all[ts])
             freebusy_data.all[ts] = [0,0,0,0];
           
           status = freebusy_data[email][ts];
           freebusy_data.all[ts][status]++;
           
           if (req)
             freebusy_data.required[ts][status]++;
         }
       }
     };
 
     // update free-busy grid with status loaded from server
     var update_freebusy_display = function(email)
     {
       var status_classes = ['unknown','free','busy','tentative','out-of-office'];
       var domid = String(email).replace(rcmail.identifier_expr, '');
       var row = $('#fbrow' + domid);
       var rowall = $('#fbrowall').children();
       var dateonly = freebusy_ui.interval > 60,
         t, ts = date2timestring(freebusy_ui.start, dateonly),
         curdate = new Date(),
         fbdata = freebusy_data[email];
 
       if (fbdata && fbdata[ts] !== undefined && row.length) {
         t = freebusy_ui.start.getTime();
         row.children().each(function(i, cell) {
           var j, n, attr, last, all_slots = [], slots = [],
             all_cell = rowall.get(i),
             cnt = dateonly ? 1 : (60 / freebusy_ui.interval),
             percent = (100 / cnt);
 
           for (n=0; n < cnt; n++) {
             curdate.setTime(t);
             ts = date2timestring(curdate, dateonly);
             attr = {
               'style': 'float:left; width:' + percent.toFixed(2) + '%',
               'class': fbdata[ts] ? status_classes[fbdata[ts]] : 'unknown'
             };
 
             slots.push($('<div>').attr(attr));
 
             // also update total row if all data was loaded
             if (!freebusy_ui.loading && freebusy_data.all[ts] && all_cell) {
               var w, all_status = freebusy_data.all[ts][2] ? 'busy' : 'unknown',
                 req_status = freebusy_data.required[ts][2] ? 'busy' : 'free';
 
               for (j=1; j < status_classes.length; j++) {
                 if (freebusy_ui.numrequired && freebusy_data.required[ts][j] >= freebusy_ui.numrequired)
                   req_status = status_classes[j];
                 if (freebusy_data.all[ts][j] == event_attendees.length)
                   all_status = status_classes[j];
               }
 
               attr['class'] = req_status + ' all-' + all_status;
 
               // these elements use some specific styling, so we want to minimize their number
               if (last && last.attr('class').startsWith(attr['class'])) {
                 w = percent + parseFloat(last.css('width').replace('%', ''));
                 last.css('width', w.toFixed(2) + '%').attr('class', attr['class'] + ' w' + w.toFixed(0));
               }
               else {
                 last = $('<div>').attr(attr).addClass('w' + percent.toFixed(0)).append('<span>');
                 all_slots.push(last);
               }
             }
 
             t += freebusy_ui.interval * 60000;
           }
 
           $(cell).html('').append(slots);
           if (all_slots.length)
             $(all_cell).html('').append(all_slots);
         });
       }
     };
     
     // write changed event date/times back to form fields
     var update_freebusy_dates = function(start, end)
     {
       // fix all-day evebt times
       if (me.selected_event.allDay) {
         var numdays = Math.floor((me.selected_event.end.getTime() - me.selected_event.start.getTime()) / DAY_MS);
         start.setHours(12);
         start.setMinutes(0);
         end.setTime(start.getTime() + numdays * DAY_MS);
         end.setHours(13);
         end.setMinutes(0);
       }
       me.selected_event.start = start;
       me.selected_event.end = end;
       freebusy_ui.startdate.val(format_date(start, settings.date_format));
       freebusy_ui.starttime.val(format_date(start, settings.time_format));
       freebusy_ui.enddate.val(format_date(end, settings.date_format));
       freebusy_ui.endtime.val(format_date(end, settings.time_format));
       freebusy_ui.needsupdate = true;
     };
 
     // attempt to find a time slot where all attemdees are available
     var freebusy_find_slot = function(dir)
     {
       // exit if free-busy data isn't available yet
       if (!freebusy_data || !freebusy_data.start)
         return false;
 
       var event = me.selected_event,
         eventstart = clone_date(event.start, event.allDay ? 1 : 0).getTime(),  // calculate with integers
         eventend = clone_date(event.end, event.allDay ? 2 : 0).getTime(),
         duration = eventend - eventstart - (event.allDay ? HOUR_MS : 0),  /* make sure we don't cross day borders on DST change */
         sinterval = freebusy_data.interval * 60000,
         intvlslots = 1,
         numslots = Math.ceil(duration / sinterval),
         fb_start = freebusy_data.start.getTime(),
         fb_end = freebusy_data.end.getTime(),
         checkdate, slotend, email, ts, slot, slotdate = new Date(),
         candidatecount = 0, candidatestart = false, success = false;
 
       // shift event times to next possible slot
       eventstart += sinterval * intvlslots * dir;
       eventend += sinterval * intvlslots * dir;
 
       // iterate through free-busy slots and find candidates
       for (slot = dir > 0 ? fb_start : fb_end - sinterval;
             (dir > 0 && slot < fb_end) || (dir < 0 && slot >= fb_start);
             slot += sinterval * dir
       ) {
         slotdate.setTime(slot);
         // fix slot if just crossed a DST change
         if (event.allDay) {
           fix_date(slotdate);
           slot = slotdate.getTime();
         }
         slotend = slot + sinterval;
 
         if ((dir > 0 && slotend <= eventstart) || (dir < 0 && slot >= eventend))  // skip
           continue;
 
         // respect workinghours setting
         if (freebusy_ui.workinhoursonly) {
           if (is_weekend(slotdate) || (freebusy_data.interval <= 60 && !is_workinghour(slotdate))) {  // skip off-hours
             candidatestart = false;
             candidatecount = 0;
             continue;
           }
         }
 
         if (!candidatestart)
           candidatestart = slot;
 
         ts = date2timestring(slotdate, freebusy_data.interval > 60);
 
         // check freebusy data for all attendees
         for (var i=0; i < event_attendees.length; i++) {
           if (freebusy_ui.attendees[i].role != 'OPT-PARTICIPANT' && (email = freebusy_ui.attendees[i].email) && freebusy_data[email] && freebusy_data[email][ts] > 1) {
             candidatestart = false;
             break;
           }
         }
         
         // occupied slot
         if (!candidatestart) {
           slot += Math.max(0, intvlslots - candidatecount - 1) * sinterval * dir;
           candidatecount = 0;
           continue;
         }
         else if (dir < 0)
           candidatestart = slot;
         
         candidatecount++;
         
         // if candidate is big enough, this is it!
         if (candidatecount == numslots) {
           event.start.setTime(candidatestart);
           event.end.setTime(candidatestart + duration);
           success = true;
           break;
         }
       }
 
       // update event date/time display
       if (success) {
         update_freebusy_dates(event.start, event.end);
         
         // move freebusy grid if necessary
         var offset = Math.ceil((event.start.getTime() - freebusy_ui.end.getTime()) / DAY_MS);
         if (event.start.getTime() >= freebusy_ui.end.getTime())
           render_freebusy_grid(Math.max(1, offset));
         else if (event.end.getTime() <= freebusy_ui.start.getTime())
           render_freebusy_grid(Math.min(-1, offset));
         else
           render_freebusy_overlay();
 
         var now = new Date(), disabled = event.start.getTime() < now.getTime();
         // FIXME: .button() does nothing in Elastic skin
         $('#schedule-find-prev').button('option', 'disabled', disabled).prop('disabled', disabled);
 
         // speak new selection
         rcmail.display_message(rcmail.gettext('suggestedslot', 'calendar') + ': ' + me.event_date_text(event, true), 'voice');
       }
       else {
         rcmail.alert_dialog(rcmail.gettext('noslotfound','calendar'));
       }
     };
 
     // update event properties and attendees availability if event times have changed
     var event_times_changed = function()
     {
       if (me.selected_event) {
         var allday = $('#edit-allday').get(0);
         me.selected_event.allDay = allday.checked;
         me.selected_event.start = me.parse_datetime(allday.checked ? '12:00' : $('#edit-starttime').val(), $('#edit-startdate').val());
         me.selected_event.end   = me.parse_datetime(allday.checked ? '13:00' : $('#edit-endtime').val(), $('#edit-enddate').val());
         if (event_attendees)
           freebusy_ui.needsupdate = true;
         $('#edit-startdate').data('duration', Math.round((me.selected_event.end.getTime() - me.selected_event.start.getTime()) / 1000));
       }
     };
 
     // add the given list of participants
     var add_attendees = function(names, params)
     {
       names = explode_quoted_string(names.replace(/,\s*$/, ''), ',');
 
       // parse name/email pairs
       var item, email, name, success = false;
       for (var i=0; i < names.length; i++) {
         email = name = '';
         item = $.trim(names[i]);
         
         if (!item.length) {
           continue;
         } // address in brackets without name (do nothing)
         else if (item.match(/^<[^@]+@[^>]+>$/)) {
           email = item.replace(/[<>]/g, '');
         } // address without brackets and without name (add brackets)
         else if (rcube_check_email(item)) {
           email = item;
         } // address with name
         else if (item.match(/([^\s<@]+@[^>]+)>*$/)) {
           email = RegExp.$1;
           name = item.replace(email, '').replace(/^["\s<>]+/, '').replace(/["\s<>]+$/, '');
         }
         if (email) {
           add_attendee($.extend({ email:email, name:name }, params));
           success = true;
         }
         else {
           rcmail.alert_dialog(rcmail.gettext('noemailwarning'));
         }
       }
       
       return success;
     };
 
     // add the given attendee to the list
     var add_attendee = function(data, readonly, before)
     {
       if (!me.selected_event)
         return false;
 
       // check for dupes...
       var exists = false;
       $.each(event_attendees, function(i, v){ exists |= (v.email == data.email); });
       if (exists)
         return false;
 
       var calendar = me.selected_event && me.calendars[me.selected_event.calendar] ? me.calendars[me.selected_event.calendar] : me.calendars[me.selected_calendar];
 
       var dispname = Q(data.name || data.email);
       dispname = '<span' + ((data.email && data.email != dispname) ? ' title="' + Q(data.email) + '"' : '') + '>' + dispname + '</span>';
 
       // role selection
       var organizer = data.role == 'ORGANIZER';
       var opts = {};
       if (organizer)
         opts.ORGANIZER = rcmail.gettext('calendar.roleorganizer');
       opts['REQ-PARTICIPANT'] = rcmail.gettext('calendar.rolerequired');
       opts['OPT-PARTICIPANT'] = rcmail.gettext('calendar.roleoptional');
       opts['NON-PARTICIPANT'] = rcmail.gettext('calendar.rolenonparticipant');
 
       if (data.cutype != 'RESOURCE')
         opts['CHAIR'] =  rcmail.gettext('calendar.rolechair');
 
       if (organizer && !readonly)
         dispname = rcmail.env['identities-selector'];
 
       var select = '<select class="edit-attendee-role form-control custom-select"'
         + (organizer || readonly ? ' disabled="true"' : '')
         + ' aria-label="' + rcmail.gettext('role','calendar') + '">';
       for (var r in opts)
         select += '<option value="'+ r +'" class="' + r.toLowerCase() + '"' + (data.role == r ? ' selected="selected"' : '') +'>' + Q(opts[r]) + '</option>';
       select += '</select>';
 
       // delete icon
       var icon = rcmail.env.deleteicon ? '<img src="' + rcmail.env.deleteicon + '" alt="" />' : '<span class="inner">' + Q(rcmail.gettext('delete')) + '</span>';
       var dellink = '<a href="#delete" class="iconlink icon button delete deletelink" title="' + Q(rcmail.gettext('delete')) + '">' + icon + '</a>';
       var tooltip = '', status = (data.status || '').toLowerCase(),
         status_label = rcmail.gettext('status' + status, 'libcalendaring');
 
       // send invitation checkbox
       var invbox = '<input type="checkbox" class="edit-attendee-reply" value="' + Q(data.email) +'" title="' + Q(rcmail.gettext('calendar.sendinvitations')) + '" '
         + (!data.noreply && settings.itip_notify & 1 ? 'checked="checked" ' : '') + '/>';
 
       if (data['delegated-to'])
         tooltip = rcmail.gettext('libcalendaring.delegatedto') + ' ' + data['delegated-to'];
       else if (data['delegated-from'])
         tooltip = rcmail.gettext('libcalendaring.delegatedfrom') + ' ' + data['delegated-from'];
       else if (!status && organizer)
         tooltip = rcmail.gettext('statusorganizer', 'libcalendaring');
       else if (status)
         tooltip = status_label;
 
       // add expand button for groups
       if (data.cutype == 'GROUP') {
         dispname += ' <a href="#expand" data-email="' + Q(data.email) + '" class="iconbutton add expandlink" title="' + rcmail.gettext('expandattendeegroup','libcalendaring') + '">' +
           rcmail.gettext('expandattendeegroup','libcalendaring') + '</a>';
       }
 
       var avail = data.email ? 'loading' : 'unknown';
       var table = rcmail.env.calendar_resources && data.cutype == 'RESOURCE' ? resources_list : attendees_list;
       var img_src = rcmail.assets_path('program/resources/blank.gif');
       var elastic = $(table).parents('.no-img').length > 0;
       var avail_tag = elastic ? ('<span class="' + avail + '"') : ('<img alt="" src="' + img_src + '" class="availabilityicon '  + avail + '"');
       var html = '<td class="role">' + select + '</td>' +
         '<td class="name"><span class="attendee-name">' + dispname + '</span></td>' +
         '<td class="availability">' + avail_tag + ' data-email="' + data.email + '" /></td>' +
         '<td class="confirmstate"><span class="attendee ' + (status || 'organizer') + '" title="' + Q(tooltip) + '">' + Q(status && !elastic ? status_label : '') + '</span></td>' +
         (data.cutype != 'RESOURCE' ? '<td class="invite">' + (organizer || readonly || !invbox ? '' : invbox) + '</td>' : '') +
         '<td class="options">' + (organizer || readonly ? '' : dellink) + '</td>';
 
       var tr = $('<tr>')
         .addClass(String(data.role).toLowerCase())
         .html(html);
 
       if (before)
         tr.insertBefore(before)
       else
         tr.appendTo(table);
 
       tr.find('a.deletelink').click({ id:(data.email || data.name) }, function(e) { remove_attendee(this, e.data.id); return false; });
       tr.find('a.expandlink').click(data, function(e) { me.expand_attendee_group(e, add_attendee, remove_attendee); return false; });
       tr.find('input.edit-attendee-reply').click(function() {
         var enabled = $('#edit-attendees-invite:checked').length || $('input.edit-attendee-reply:checked').length;
         $('#eventedit .attendees-commentbox')[enabled ? 'show' : 'hide']();
       });
 
       // select organizer identity
       if (data.identity_id)
         $('#edit-identities-list').val(data.identity_id);
 
       // check free-busy status
       if (avail == 'loading') {
         check_freebusy_status(tr.find('.availability > *:first'), data.email, me.selected_event);
       }
 
       // Make Elastic checkboxes pretty
       if (window.UI && UI.pretty_checkbox) {
         $(tr).find('input[type=checkbox]').each(function() { UI.pretty_checkbox(this); });
         $(tr).find('select').each(function() { UI.pretty_select(this); });
       }
 
       event_attendees.push(data);
       return true;
     };
 
     // iterate over all attendees and update their free-busy status display
     var update_freebusy_status = function(event)
     {
       attendees_list.find('.availability > *').each(function(i,v) {
         var email, icon = $(this);
         if (email = icon.attr('data-email'))
           check_freebusy_status(icon, email, event);
       });
       
       freebusy_ui.needsupdate = false;
     };
     
     // load free-busy status from server and update icon accordingly
     var check_freebusy_status = function(icon, email, event)
     {
       var calendar = event.calendar && me.calendars[event.calendar] ? me.calendars[event.calendar] : { freebusy:false };
       if (!calendar.freebusy) {
         $(icon).attr('class', 'availabilityicon unknown');
         return;
       }
       
       icon = $(icon).attr('class', 'availabilityicon loading');
       
       $.ajax({
         type: 'GET',
         dataType: 'html',
         url: rcmail.url('freebusy-status'),
         data: { email:email, start:date2servertime(clone_date(event.start, event.allDay?1:0)), end:date2servertime(clone_date(event.end, event.allDay?2:0)), _remote: 1 },
         success: function(status){
           var avail = String(status).toLowerCase();
           icon.removeClass('loading').addClass(avail).attr('title', rcmail.gettext('avail' + avail, 'calendar'));
         },
         error: function(){
           icon.removeClass('loading').addClass('unknown').attr('title', rcmail.gettext('availunknown', 'calendar'));
         }
       });
     };
     
     // remove an attendee from the list
     var remove_attendee = function(elem, id)
     {
       $(elem).closest('tr').remove();
       event_attendees = $.grep(event_attendees, function(data){ return (data.name != id && data.email != id) });
     };
 
     // open a dialog to display detailed free-busy information and to find free slots
     var event_resources_dialog = function(search)
     {
       var $dialog = $('#eventresourcesdialog');
 
       if ($dialog.is(':ui-dialog'))
         $dialog.dialog('close');
 
       // dialog buttons
       var buttons = [
         {
           text: rcmail.gettext('addresource', 'calendar'),
           'class': 'mainaction save',
           click: function() { rcmail.command('add-resource'); $dialog.dialog("close"); }
         },
         {
           text: rcmail.gettext('close'),
           'class': 'cancel',
           click: function() { $dialog.dialog("close"); }
         }
       ];
 
       var resize = function() {
         var container = $(rcmail.gui_objects.resourceinfocalendar);
         container.fullCalendar('option', 'height', container.height() + 1);
       };
 
       // open jquery UI dialog
       $dialog.dialog({
         modal: true,
         resizable: false, // prevents from Availability tab reflow bugs on resize
         closeOnEscape: true,
         title: rcmail.gettext('findresources', 'calendar'),
         classes: {'ui-dialog': 'selection-dialog resources-dialog'},
         open: function() {
           rcmail.ksearch_blur();
           $dialog.attr('aria-hidden', 'false');
 
           // for Elastic
           if ($('html.layout-small,html.layout-phone').length) {
             $('#eventresourcesdialog .resource-selection').css('display', 'flex');
             $('#eventresourcesdialog .resource-content').css('display', 'none');
           }
           setTimeout(resize, 50);
         },
         close: function() {
           $dialog.dialog('destroy').attr('aria-hidden', 'true').hide();
         },
         resize: resize,
         buttons: buttons,
         width: 900,
         height: 500
       }).show();
 
       $('.ui-dialog-buttonset .ui-button', $dialog.parent()).first().attr('id', 'rcmbtncalresadd');
 
       me.dialog_resize($dialog.get(0), 540, Math.min(1000, $(window).width() - 50));
 
       // set search query
       $('#resourcesearchbox').val(search || '');
 
       // initialize the treelist widget
       if (!resources_treelist) {
         resources_treelist = new rcube_treelist_widget(rcmail.gui_objects.resourceslist, {
           id_prefix: 'rcres',
           id_encode: rcmail.html_identifier_encode,
           id_decode: rcmail.html_identifier_decode,
           selectable: true,
           save_state: true
         });
         resources_treelist.addEventListener('select', function(node) {
           if (resources_data[node.id]) {
             resource_showinfo(resources_data[node.id]);
             rcmail.enable_command('add-resource', me.selected_event && $("#eventedit").is(':visible') ? true : false);
 
             // on elastic mobile display resource info box
             if ($('html.layout-small,html.layout-phone').length) {
               $('#eventresourcesdialog .resource-selection').css('display', 'none');
               $('#eventresourcesdialog .resource-content').css('display', 'flex');
               $(window).resize();
               resize();
             }
           }
           else {
             rcmail.enable_command('add-resource', false);
             $(rcmail.gui_objects.resourceinfo).hide();
             $(rcmail.gui_objects.resourceownerinfo).hide();
             $(rcmail.gui_objects.resourceinfocalendar).fullCalendar('removeEventSources');
           }
         });
 
         // fetch (all) resource data from server
         me.loading_lock = rcmail.set_busy(true, 'loading', me.loading_lock);
         rcmail.http_request('resources-list', {}, me.loading_lock);
 
         // register button
         rcmail.register_button('add-resource', 'rcmbtncalresadd', 'uibutton');
 
         // initialize resource calendar display
         var resource_cal = $(rcmail.gui_objects.resourceinfocalendar);
         resource_cal.fullCalendar($.extend({}, fullcalendar_defaults, {
           header: { left: '', center: '', right: '' },
           height: resource_cal.height() + 4,
           defaultView: 'agendaWeek',
           eventSources: [],
           slotMinutes: 60,
           allDaySlot: false,
           eventRender: function(event, element, view) {
             var title = rcmail.get_label(event.status, 'calendar');
             element.addClass('status-' + event.status);
             element.find('.fc-title').text(title);
             element.attr('aria-label', me.event_date_text(event, true) + ': ' + title);
           }
         }));
 
         $('#resource-calendar-prev').click(function(){
           resource_cal.fullCalendar('prev');
           return false;
         });
         $('#resource-calendar-next').click(function(){
           resource_cal.fullCalendar('next');
           return false;
         });
       }
       else if (search) {
         resource_search();
       }
       else {
         resource_render_list(resources_index);
       }
 
       if (me.selected_event && me.selected_event.start) {
         $(rcmail.gui_objects.resourceinfocalendar).fullCalendar('gotoDate', me.selected_event.start);
       }
     };
 
     // render the resource details UI box
     var resource_showinfo = function(resource)
     {
       // inline function to render a resource attribute
       function render_attrib(value) {
         if (typeof value == 'boolean') {
           return value ? rcmail.get_label('yes') : rcmail.get_label('no');
         }
 
         return value;
       }
 
       if (rcmail.gui_objects.resourceinfo) {
         var tr, table = $(rcmail.gui_objects.resourceinfo).show().find('tbody').html(''),
           attribs = $.extend({ name:resource.name }, resource.attributes||{})
           attribs.description = resource.description;
 
         for (var k in attribs) {
           if (typeof attribs[k] == 'undefined')
             continue;
           table.append($('<tr>').addClass(k + ' form-group row')
             .append('<td class="title col-sm-4"><label class="col-form-label">' + Q(ucfirst(rcmail.get_label(k, 'calendar'))) + '</label></td>')
             .append('<td class="value col-sm-8 form-control-plaintext">' + text2html(render_attrib(attribs[k])) + '</td>')
           );
         }
 
         $(rcmail.gui_objects.resourceownerinfo).hide();
         $(rcmail.gui_objects.resourceinfocalendar).fullCalendar('removeEventSources');
 
         if (resource.owner) {
           // display cached data
           if (resource_owners[resource.owner]) {
             resource_owner_load(resource_owners[resource.owner]);
           }
           else {
             // fetch owner data from server
             me.loading_lock = rcmail.set_busy(true, 'loading', me.loading_lock);
             rcmail.http_request('resources-owner', { _id: resource.owner }, me.loading_lock);
           }
         }
 
         // load resource calendar
         resources_events_source.url = "./?_task=calendar&_action=resources-calendar&_id="+urlencode(resource.ID);
         $(rcmail.gui_objects.resourceinfocalendar).fullCalendar('addEventSource', resources_events_source);
       }
     };
 
     // callback from server for resource listing
     var resource_data_load = function(data)
     {
       var resources_tree = {};
 
       // store data by ID
       $.each(data, function(i, rec) {
         resources_data[rec.ID] = rec;
 
         // assign parent-relations
         if (rec.members) {
           $.each(rec.members, function(j, m){
             resources_tree[m] = rec.ID;
           });
         }
       });
 
       // walk the parent-child tree to determine the depth of each node
       $.each(data, function(i, rec) {
         rec._depth = 0;
         if (resources_tree[rec.ID])
           rec.parent_id = resources_tree[rec.ID];
 
         var parent_id = resources_tree[rec.ID];
         while (parent_id) {
           rec._depth++;
           parent_id = resources_tree[parent_id];
         }
       });
 
       // sort by depth, collection and name
       data.sort(function(a,b) {
         var j = a._type == 'collection' ? 1 : 0,
             k = b._type == 'collection' ? 1 : 0,
             d = a._depth - b._depth;
         if (!d) d = (k - j);
         if (!d) d = b.name < a.name ? 1 : -1;
         return d;
       });
 
       $.each(data, function(i, rec) {
         resources_index.push(rec.ID);
       });
 
       // apply search filter...
       if ($('#resourcesearchbox').val() != '')
         resource_search();
       else  // ...or render full list
         resource_render_list(resources_index);
 
       rcmail.set_busy(false, null, me.loading_lock);
     };
 
     // renders the given list of resource records into the treelist
     var resource_render_list = function(index) {
       var rec, link;
 
       resources_treelist.reset();
 
       $.each(index, function(i, dn) {
         if (rec = resources_data[dn]) {
           link = $('<a>').attr('href', '#')
             .attr('rel', rec.ID)
             .html(Q(rec.name));
 
           resources_treelist.insert({ id:rec.ID, html:link, classes:[rec._type], collapsed:true }, rec.parent_id, false);
         }
       });
     };
 
     // callback from server for owner information display
     var resource_owner_load = function(data)
     {
       if (data) {
         // cache this!
         resource_owners[data.ID] = data;
 
         var table = $(rcmail.gui_objects.resourceownerinfo).find('tbody').html('');
 
         for (var k in data) {
           if (k == 'event' || k == 'ID')
             continue;
 
           table.append($('<tr>').addClass(k)
             .append('<td class="title">' + Q(ucfirst(rcmail.get_label(k, 'calendar'))) + '</td>')
             .append('<td class="value">' + text2html(data[k]) + '</td>')
           );
         }
 
         table.parent().show();
       }
     }
 
     // quick-filter the loaded resource data
     var resource_search = function()
     {
       var dn, rec, dataset = [],
         q = $('#resourcesearchbox').val().toLowerCase();
 
       if (q.length && resources_data) {
         // search by iterating over all resource records
         for (dn in resources_data) {
           rec = resources_data[dn];
           if ((rec.name && String(rec.name).toLowerCase().indexOf(q) >= 0)
             || (rec.email && String(rec.email).toLowerCase().indexOf(q) >= 0)
             || (rec.description && String(rec.description).toLowerCase().indexOf(q) >= 0)
           ) {
             dataset.push(rec.ID);
           }
         }
 
         resource_render_list(dataset);
 
         // select single match
         if (dataset.length == 1) {
           resources_treelist.select(dataset[0]);
         }
       }
       else {
         $('#resourcesearchbox').val('');
       }
     };
 
     // 
     var reset_resource_search = function()
     {
       $('#resourcesearchbox').val('').focus();
       resource_render_list(resources_index);
     };
 
     // 
     var add_resource2event = function()
     {
       var resource = resources_data[resources_treelist.get_selection()];
       if (resource) {
         if (add_attendee($.extend({ role:'REQ-PARTICIPANT', status:'NEEDS-ACTION', cutype:'RESOURCE' }, resource)))
           rcmail.display_message(rcmail.get_label('resourceadded', 'calendar'), 'confirmation');
       }
     }
 
     // when the user accepts or declines an event invitation
     var event_rsvp = function(response, delegate, replymode)
     {
       var btn;
       if (typeof response == 'object') {
         btn = $(response);
         response = btn.attr('rel')
       }
       else {
         btn = $('#event-rsvp input.button[rel='+response+']');
       }
 
       // show menu to select rsvp reply mode (current or all)
       if (me.selected_event && me.selected_event.recurrence && !replymode) {
         rcube_libcalendaring.itip_rsvp_recurring(btn, function(resp, mode) {
           event_rsvp(resp, null, mode);
         });
         return;
       }
 
       if (me.selected_event && me.selected_event.attendees && response) {
         // bring up delegation dialog
         if (response == 'delegated' && !delegate) {
           rcube_libcalendaring.itip_delegate_dialog(function(data) {
             data.rsvp = data.rsvp ? 1 : '';
             event_rsvp('delegated', data, replymode);
           });
           return;
         }
 
         // update attendee status
         attendees = [];
         for (var data, i=0; i < me.selected_event.attendees.length; i++) {
           data = me.selected_event.attendees[i];
           if (settings.identity.emails.indexOf(';'+String(data.email).toLowerCase()) >= 0) {
             data.status = response.toUpperCase();
             data.rsvp = 0;  // unset RSVP flag
 
             if (data.status == 'DELEGATED') {
               data['delegated-to'] = delegate.to;
               data.rsvp = delegate.rsvp
             }
             else {
               if (data['delegated-to']) {
                 delete data['delegated-to'];
                 if (data.role == 'NON-PARTICIPANT' && data.status != 'DECLINED')
                   data.role = 'REQ-PARTICIPANT';
               }
             }
 
             attendees.push(i)
           }
           else if (response != 'DELEGATED' && data['delegated-from'] &&
               settings.identity.emails.indexOf(';'+String(data['delegated-from']).toLowerCase()) >= 0) {
             delete data['delegated-from'];
           }
 
           // set free_busy status to transparent if declined (#4425)
           if (data.status == 'DECLINED' || data.role == 'NON-PARTICIPANT') {
             me.selected_event.free_busy = 'free';
           }
           else {
             me.selected_event.free_busy = 'busy';
           }
         }
 
         // submit status change to server
         var submit_data = $.extend({}, me.selected_event, { source:null, comment:$('#reply-comment-event-rsvp').val(), _savemode: replymode || 'all' }, (delegate || {})),
           noreply = $('#noreply-event-rsvp:checked').length ? 1 : 0;
 
         // import event from mail (temporary iTip event)
         if (submit_data._mbox && submit_data._uid) {
           me.saving_lock = rcmail.set_busy(true, 'calendar.savingdata');
           rcmail.http_post('mailimportitip', {
             _mbox: submit_data._mbox,
             _uid:  submit_data._uid,
             _part: submit_data._part,
             _status:  response,
             _to: (delegate ? delegate.to : null),
             _rsvp: (delegate && delegate.rsvp) ? 1 : 0,
             _noreply: noreply,
             _comment: submit_data.comment,
             _instance: submit_data._instance,
             _savemode: submit_data._savemode
           });
         }
         else if (settings.invitation_calendars) {
           update_event('rsvp', submit_data, { status:response, noreply:noreply, attendees:attendees });
         }
         else {
           me.saving_lock = rcmail.set_busy(true, 'calendar.savingdata');
           rcmail.http_post('calendar/event', { action:'rsvp', e:submit_data, status:response, attendees:attendees, noreply:noreply });
         }
 
         event_show_dialog(me.selected_event);
       }
     };
 
     // add the given date to the RDATE list
     var add_rdate = function(date)
     {
       var li = $('<li>')
         .attr('data-value', date2servertime(date))
         .append($('<span>').text(format_date(date, settings.date_format)))
         .appendTo('#edit-recurrence-rdates');
 
       $('<a>').attr('href', '#del')
         .addClass('iconbutton delete')
         .html(rcmail.get_label('delete', 'calendar'))
         .attr('title', rcmail.get_label('delete', 'calendar'))
         .appendTo(li);
     };
 
     // re-sort the list items by their 'data-value' attribute
     var sort_rdates = function()
     {
       var mylist = $('#edit-recurrence-rdates'),
         listitems = mylist.children('li').get();
       listitems.sort(function(a, b) {
          var compA = $(a).attr('data-value');
          var compB = $(b).attr('data-value');
          return (compA < compB) ? -1 : (compA > compB) ? 1 : 0;
       })
       $.each(listitems, function(idx, item) { mylist.append(item); });
     }
 
     // remove the link reference matching the given uri
     function remove_link(elem)
     {
       var $elem = $(elem), uri = $elem.attr('data-uri');
 
       me.selected_event.links = $.grep(me.selected_event.links, function(link) { return link.uri != uri; });
 
       // remove UI list item
       $elem.hide().closest('li').addClass('deleted');
     }
 
     // post the given event data to server
     var update_event = function(action, data, add)
     {
       me.saving_lock = rcmail.set_busy(true, 'calendar.savingdata');
       rcmail.http_post('calendar/event', $.extend({ action:action, e:data }, (add || {})));
 
       // render event temporarily into the calendar
       if ((data.start && data.end) || data.id) {
         var tmp, event = data.id ? $.extend(fc.fullCalendar('clientEvents', data.id)[0], data) : data;
 
         if (data.start)
           event.start = data.start;
         if (data.end)
           event.end = data.end;
         if (data.allDay !== undefined)
           event.allDay = !!data.allDay; // must be boolean for fullcalendar
 
         // For fullCalendar all-day event's end date must be exclusive
         if (event.allDay && data.end && (tmp = moment(data.end)) && tmp.format('Hms') !== '000') {
           event.end = moment().year(tmp.year()).month(tmp.month()).date(tmp.date()).hour(0).minute(0).second(0).add(1, 'days');
         }
 
         event.editable = false;
         event.temp = true;
         event.className = ['fc-event-cal-'+data.calendar, 'fc-event-temp'];
 
         fc.fullCalendar(data.id ? 'updateEvent' : 'renderEvent', event);
 
         // mark all recurring instances as temp
         if (event.recurrence || event.recurrence_id) {
           var base_id = event.recurrence_id ? event.recurrence_id : String(event.id).replace(/-\d+(T\d{6})?$/, '');
           $.each(fc.fullCalendar('clientEvents', function(e){ return e.id == base_id || e.recurrence_id == base_id; }), function(i,ev) {
             ev.temp = true;
             ev.editable = false;
             event.className.push('fc-event-temp');
             fc.fullCalendar('updateEvent', ev);
           });
         }
       }
     };
 
     // mouse-click handler to check if the show dialog is still open and prevent default action
     var dialog_check = function(e)
     {
       var showd = $("#eventshow");
       if (showd.is(':visible') && !$(e.target).closest('.ui-dialog').length && !$(e.target).closest('.popupmenu').length) {
         showd.dialog('close');
         e.stopImmediatePropagation();
         ignore_click = true;
         return false;
       }
       else if (ignore_click) {
         window.setTimeout(function(){ ignore_click = false; }, 20);
         return false;
       }
       return true;
     };
 
     // display confirm dialog when modifying/deleting an event
     var update_event_confirm = function(action, event, data)
     {
       // Allow other plugins to do actions here
       // E.g. when you move/resize the event init wasn't called
       // but we need it as some plugins may modify user identities
       // we depend on here (kolab_delegation)
       rcmail.triggerEvent('calendar-event-init', {o: event});
 
       if (!data) data = event;
       var decline = false, notify = false, html = '', cal = me.calendars[event.calendar],
         _has_attendees = me.has_attendees(event),
         _is_attendee = _has_attendees && me.is_attendee(event),
         _is_organizer = me.is_organizer(event);
 
       // event has attendees, ask whether to notify them
       if (_has_attendees) {
         var checked = (settings.itip_notify & 1 ? ' checked="checked"' : '');
 
         if (action == 'remove' && cal.group != 'shared' && !_is_organizer && _is_attendee) {
           decline = true;
           checked = event.status != 'CANCELLED' ? checked : '';
           html += '<div class="message dialog-message ui alert boxwarning">' +
             '<label><input class="confirm-attendees-decline" type="checkbox"' + checked + ' value="1" name="decline" />&nbsp;' +
             rcmail.gettext('itipdeclineevent', 'calendar') + 
             '</label></div>';
         }
         else if (_is_organizer) {
           notify = true;
           if (settings.itip_notify & 2) {
             html += '<div class="message dialog-message ui alert boxwarning">' +
               '<label><input class="confirm-attendees-donotify" type="checkbox"' + checked + ' value="1" name="notify" />&nbsp;' +
                 rcmail.gettext((action == 'remove' ? 'sendcancellation' : 'sendnotifications'), 'calendar') +
               '</label></div>';
           }
           else {
             data._notify = settings.itip_notify;
           }
         }
       }
 
       // recurring event: user needs to select the savemode
       if (event.recurrence) {
         var future_disabled = '', message_label = (action == 'remove' ? 'removerecurringeventwarning' : 'changerecurringeventwarning');
 
         // disable the 'future' savemode if I'm an attendee
         // reason: no calendaring system supports the thisandfuture range parameter in iTip REPLY
         if (action == 'remove' && !_is_organizer && _is_attendee) {
           future_disabled = ' disabled';
         }
 
         html += '<div class="message dialog-message ui alert boxwarning">' + rcmail.gettext(message_label, 'calendar') + '</div>' +
           '<div class="savemode">' +
             '<a href="#current" class="button btn btn-secondary">' + rcmail.gettext('currentevent', 'calendar') + '</a>' +
             '<a href="#future" class="button btn btn-secondary' + future_disabled + '">' + rcmail.gettext('futurevents', 'calendar') + '</a>' +
             '<a href="#all" class="button btn btn-secondary">' + rcmail.gettext('allevents', 'calendar') + '</a>' +
             (action != 'remove' ? '<a href="#new" class="button btn btn-secondary">' + rcmail.gettext('saveasnew', 'calendar') + '</a>' : '') +
           '</div>';
       }
       
       // show dialog
       if (html) {
         var $dialog = $('<div>').html(html);
       
         $dialog.find('a.button').button().filter(':not(.disabled)').click(function(e) {
           data._savemode = String(this.href).replace(/.+#/, '');
           data._notify = settings.itip_notify;
 
           // open event edit dialog when saving as new
           if (data._savemode == 'new') {
             event._savemode = 'new';
             event_edit_dialog('edit', event);
             fc.fullCalendar('refetchEvents');
           }
           else {
             if ($dialog.find('input.confirm-attendees-donotify').length)
               data._notify = $dialog.find('input.confirm-attendees-donotify').get(0).checked ? 1 : 0;
             if (decline) {
               data._decline = $dialog.find('input.confirm-attendees-decline:checked').length;
               data._notify = 0;
             }
             update_event(action, data);
           }
 
           $dialog.dialog("close");
           return false;
         });
         
         var buttons = [];
 
         if (!event.recurrence) {
           buttons.push({
             text: rcmail.gettext((action == 'remove' ? 'delete' : 'save'), 'calendar'),
             'class': action == 'remove' ? 'delete mainaction' : 'save mainaction',
             click: function() {
               data._notify = notify && $dialog.find('input.confirm-attendees-donotify:checked').length ? 1 : 0;
               data._decline = decline && $dialog.find('input.confirm-attendees-decline:checked').length ? 1 : 0;
               update_event(action, data);
               $(this).dialog("close");
             }
           });
         }
 
         buttons.push({
           text: rcmail.gettext('cancel', 'calendar'),
           'class': 'cancel',
           click: function() {
             $(this).dialog("close");
           }
         });
 
         $dialog.dialog({
           modal: true,
           width: 460,
           dialogClass: 'warning',
           title: rcmail.gettext((action == 'remove' ? 'removeeventconfirm' : 'changeeventconfirm'), 'calendar'),
           buttons: buttons,
           open: function() {
             setTimeout(function(){
               $dialog.parent().find('.ui-button:not(.ui-dialog-titlebar-close)').first().focus();
             }, 5);
           },
           close: function(){
             $dialog.dialog("destroy").remove();
             if (!rcmail.busy)
               fc.fullCalendar('refetchEvents');
           }
         }).addClass('event-update-confirm').show();
 
         return false;
       }
       // show regular confirm box when deleting
       else if (action == 'remove' && !cal.undelete) {
         if (!confirm(rcmail.gettext('deleteventconfirm', 'calendar')))
           return false;
       }
 
       // do update
       update_event(action, data);
 
       return true;
     };
 
 
     /*** public methods ***/
 
     /**
      * Remove saving lock and free the UI for new input
      */
     this.unlock_saving = function()
     {
         if (me.saving_lock)
             rcmail.set_busy(false, null, me.saving_lock);
     };
 
     // opens the given calendar in a popup dialog
     this.quickview = function(id, shift)
     {
       var src, in_quickview = false;
       $.each(this.quickview_sources, function(i,cal) {
         if (cal.id == id) {
           in_quickview = true;
           src = cal;
         }
       });
 
       // remove source from quickview
       if (in_quickview && shift) {
         this.quickview_sources = $.grep(this.quickview_sources, function(src) { return src.id != id; });
       }
       else {
         if (!shift) {
           // remove all current quickview event sources
           if (this.quickview_active) {
             fc.fullCalendar('removeEventSources');
           }
 
           this.quickview_sources = [];
 
           // uncheck all active quickview icons
           calendars_list.container.find('div.focusview')
             .add('#calendars .searchresults div.focusview')
             .removeClass('focusview')
               .find('a.quickview').attr('aria-checked', 'false');
         }
 
         if (!in_quickview) {
           // clone and modify calendar properties
           src = $.extend({}, this.calendars[id]);
           src.url += '&_quickview=1';
           this.quickview_sources.push(src);
         }
       }
 
       // disable quickview
       if (this.quickview_active && !this.quickview_sources.length) {
         // register regular calendar event sources
         $.each(this.calendars, function(k, cal) {
           if (cal.active)
             fc.fullCalendar('addEventSource', cal);
         });
 
         this.quickview_active = false;
         $('body').removeClass('quickview-active');
 
         // uncheck all active quickview icons
         calendars_list.container.find('div.focusview')
           .add('#calendars .searchresults div.focusview')
           .removeClass('focusview')
             .find('a.quickview').attr('aria-checked', 'false');
       }
       // activate quickview
       else if (!this.quickview_active) {
         // remove regular calendar event sources
         fc.fullCalendar('removeEventSources');
 
         // register quickview event sources
         $.each(this.quickview_sources, function(i, src) {
           fc.fullCalendar('addEventSource', src);
         });
 
         this.quickview_active = true;
         $('body').addClass('quickview-active');
       }
       // update quickview sources
       else if (in_quickview) {
         fc.fullCalendar('removeEventSource', src);
       }
       else if (src) {
         fc.fullCalendar('addEventSource', src);
       }
 
       // activate quickview icon
       if (this.quickview_active) {
         $(calendars_list.get_item(id)).find('.calendar').first()
           .add('#calendars .searchresults .cal-' + id)
           [in_quickview ? 'removeClass' : 'addClass']('focusview')
             .find('a.quickview').attr('aria-checked', in_quickview ? 'false' : 'true');
       }
     };
 
     // disable quickview mode
     function reset_quickview()
     {
       // remove all current quickview event sources
       if (me.quickview_active) {
         fc.fullCalendar('removeEventSources');
         me.quickview_sources = [];
       }
 
       // register regular calendar event sources
       $.each(me.calendars, function(k, cal) {
         if (cal.active)
           fc.fullCalendar('addEventSource', cal);
       });
 
       // uncheck all active quickview icons
       calendars_list.container.find('div.focusview')
         .add('#calendars .searchresults div.focusview')
         .removeClass('focusview')
           .find('a.quickview').attr('aria-checked', 'false');
 
       me.quickview_active = false;
       $('body').removeClass('quickview-active');
     };
 
     //public method to show the print dialog.
     this.print_calendars = function(view)
     {
       if (!view) view = fc.fullCalendar('getView').name;
       var date = fc.fullCalendar('getDate').toDate();
 
       rcmail.open_window(rcmail.url('print', {
           view: view,
           date: date2unixtime(date),
           range: settings.agenda_range,
           search: this.search_query
         }), true, true);
     };
 
     // public method to bring up the new event dialog
     this.add_event = function(templ) {
       if (this.selected_calendar) {
         var now = new Date();
         var date = fc.fullCalendar('getDate').toDate();
         date.setHours(now.getHours()+1);
         date.setMinutes(0);
         var end = new Date(date.getTime());
         end.setHours(date.getHours()+1);
         event_edit_dialog('new', $.extend({ start:date, end:end, allDay:false, calendar:this.selected_calendar }, templ || {}));
       }
     };
 
     // delete the given event after showing a confirmation dialog
     this.delete_event = function(event) {
       // show confirm dialog for recurring events, use jquery UI dialog
       return update_event_confirm('remove', event, { id:event.id, calendar:event.calendar, attendees:event.attendees });
     };
 
     // opens a jquery UI dialog with event properties (or empty for creating a new calendar)
     this.calendar_edit_dialog = function(calendar)
     {
       if (!calendar)
         calendar = { name:'', color:'cc0000', editable:true, showalarms:true };
 
       var title = rcmail.gettext((calendar.id ? 'editcalendar' : 'createcalendar'), 'calendar'),
         params = {action: calendar.id ? 'form-edit' : 'form-new', c: {id: calendar.id}, _framed: 1},
         $dialog = $('<iframe>').attr('src', rcmail.url('calendar', params)).on('load', function() {
           var contents = $(this).contents();
           contents.find('#calendar-name')
             .prop('disabled', !calendar.editable)
             .val(calendar.editname || calendar.name)
             .select();
           contents.find('#calendar-color')
             .val(calendar.color);
           contents.find('#calendar-showalarms')
             .prop('checked', calendar.showalarms);
         }),
         save_func = function() {
           var data,
             form = $dialog.contents().find('#calendarpropform'),
             name = form.find('#calendar-name');
 
           // form is not loaded
           if (!form || !form.length)
             return false;
 
           // do some input validation
           if (!name.val() || name.val().length < 2) {
             rcmail.alert_dialog(rcmail.gettext('invalidcalendarproperties', 'calendar'), function() {
               name.select();
             });
 
             return false;
           }
 
           // post data to server
           data = form.serializeJSON();
           if (data.color)
             data.color = data.color.replace(/^#/, '');
           if (calendar.id)
             data.id = calendar.id;
 
           me.saving_lock = rcmail.set_busy(true, 'calendar.savingdata');
           rcmail.http_post('calendar', { action:(calendar.id ? 'edit' : 'new'), c:data });
           $dialog.dialog("close");
         };
 
       rcmail.simple_dialog($dialog, title, save_func, {
         width: 600,
         height: 400
       });
     };
 
     this.calendar_remove = function(calendar)
     {
       this.calendar_destroy_source(calendar.id);
       rcmail.http_post('calendar', { action:'subscribe', c:{ id:calendar.id, active:0, permanent:0, recursive:1 } });
       return true;
     };
 
     this.calendar_delete = function(calendar)
     {
       var label = calendar.children ? 'deletecalendarconfirmrecursive' : 'deletecalendarconfirm';
       rcmail.confirm_dialog(rcmail.gettext(label, 'calendar'), 'delete', function() {
         rcmail.http_post('calendar', { action:'delete', c:{ id:calendar.id } });
         return true;
       });
 
       return false;
     };
 
     this.calendar_refresh_source = function(id)
     {
       // got race-conditions fc.currentFetchID when using refetchEventSources,
       // so we remove and add the source instead
       // fc.fullCalendar('refetchEventSources', me.calendars[id]);
       // TODO: Check it again with fullcalendar >= 3.9
       fc.fullCalendar('removeEventSource', me.calendars[id]);
       fc.fullCalendar('addEventSource', me.calendars[id]);
     };
 
     this.calendar_destroy_source = function(id)
     {
       var delete_ids = [];
 
       if (this.calendars[id]) {
         // find sub-calendars
         if (this.calendars[id].children) {
           for (var child_id in this.calendars) {
             if (String(child_id).indexOf(id) == 0)
               delete_ids.push(child_id);
           }
         }
         else {
           delete_ids.push(id);
         }
       }
 
       // delete all calendars in the list
       for (var i=0; i < delete_ids.length; i++) {
         id = delete_ids[i];
         calendars_list.remove(id);
         fc.fullCalendar('removeEventSource', this.calendars[id]);
         $('#edit-calendar option[value="'+id+'"]').remove();
         delete this.calendars[id];
       }
 
       if (this.selected_calendar == id) {
         this.init_calendars(true);
       }
     };
 
     // open a dialog to upload an .ics file with events to be imported
     this.import_events = function(calendar)
     {
       // close show dialog first
       var $dialog = $("#eventsimport"),
         form = rcmail.gui_objects.importform;
 
       if ($dialog.is(':ui-dialog'))
         $dialog.dialog('close');
 
       if (calendar)
         $('#event-import-calendar').val(calendar.id);
 
       var buttons = [
         {
           text: rcmail.gettext('import', 'calendar'),
           'class' : 'mainaction import',
           click: function() {
             if (form && form.elements._data.value) {
               rcmail.async_upload_form(form, 'import_events', function(e) {
                 rcmail.set_busy(false, null, me.saving_lock);
                 $('.ui-dialog-buttonpane button', $dialog.parent()).button('enable');
 
                 // display error message if no sophisticated response from server arrived (e.g. iframe load error)
                 if (me.import_succeeded === null)
                   rcmail.display_message(rcmail.get_label('importerror', 'calendar'), 'error');
               });
 
               // display upload indicator (with extended timeout)
               var timeout = rcmail.env.request_timeout;
               rcmail.env.request_timeout = 600;
               me.import_succeeded = null;
               me.saving_lock = rcmail.set_busy(true, 'uploading');
               $('.ui-dialog-buttonpane button', $dialog.parent()).button('disable');
 
               // restore settings
               rcmail.env.request_timeout = timeout;
             }
           }
         },
         {
           text: rcmail.gettext('cancel', 'calendar'),
           'class': 'cancel',
           click: function() { $dialog.dialog("close"); }
         }
       ];
 
       // open jquery UI dialog
       $dialog.dialog({
         modal: true,
         resizable: false,
         closeOnEscape: false,
         title: rcmail.gettext('importevents', 'calendar'),
         close: function() {
           $('.ui-dialog-buttonpane button', $dialog.parent()).button('enable');
           $dialog.dialog("destroy").hide();
         },
         buttons: buttons,
         width: 520
       }).show();
     };
 
     // callback from server if import succeeded
     this.import_success = function(p)
     {
       this.import_succeeded = true;
       $("#eventsimport:ui-dialog").dialog('close');
       rcmail.set_busy(false, null, me.saving_lock);
       rcmail.gui_objects.importform.reset();
 
       if (p.refetch)
         this.refresh(p);
     };
 
     // callback from server to report errors on import
     this.import_error = function(p)
     {
       this.import_succeeded = false;
       rcmail.set_busy(false, null, me.saving_lock);
       rcmail.display_message(p.message || rcmail.get_label('importerror', 'calendar'), 'error');
     }
 
     // open a dialog to select calendars for export
     this.export_events = function(calendar)
     {
       // close show dialog first
       var $dialog = $("#eventsexport"),
         form = rcmail.gui_objects.exportform;
 
       if ($dialog.is(':ui-dialog'))
         $dialog.dialog('close');
 
       if (calendar)
         $('#event-export-calendar').val(calendar.id);
 
       $('#event-export-range').change(function(e){
         var custom = $('option:selected', this).val() == 'custom',
           input = $('#event-export-startdate')
         input.parent()[(custom?'show':'hide')]();
         if (custom)
           input.select();
       })
 
       var buttons = [
         {
           text: rcmail.gettext('export', 'calendar'),
           'class': 'mainaction export',
           click: function() {
             if (form) {
               var start = 0, range = $('#event-export-range option:selected', this).val(),
                 source = $('#event-export-calendar option:selected').val(),
                 attachmt = $('#event-export-attachments').get(0).checked;
 
               if (range == 'custom')
                 start = date2unixtime(me.parse_datetime('00:00', $('#event-export-startdate').val()));
               else if (range > 0)
                 start = 'today -' + range + ' months';
 
               rcmail.goto_url('export_events', { source:source, start:start, attachments:attachmt?1:0 }, false);
             }
             $dialog.dialog("close");
           }
         },
         {
           text: rcmail.gettext('cancel', 'calendar'),
           'class': 'cancel',
           click: function() { $dialog.dialog("close"); }
         }
       ];
 
       // open jquery UI dialog
       $dialog.dialog({
         modal: true,
         resizable: false,
         closeOnEscape: false,
         title: rcmail.gettext('exporttitle', 'calendar'),
         close: function() {
           $('.ui-dialog-buttonpane button', $dialog.parent()).button('enable');
           $dialog.dialog("destroy").hide();
         },
         buttons: buttons,
         width: 520
       }).show();
     };
 
     // download the selected event as iCal
     this.event_download = function(event)
     {
       if (event && event.id) {
         rcmail.goto_url('export_events', { source:event.calendar, id:event.id, attachments:1 }, false);
       }
     };
 
     // open the message compose step with a calendar_event parameter referencing the selected event.
     // the server-side plugin hook will pick that up and attach the event to the message.
     this.event_sendbymail = function(event, e)
     {
       if (event && event.id) {
         rcmail.command('compose', { _calendar_event:event._id }, e ? e.target : null, e);
       }
     };
 
     // display the edit dialog, request 'new' action and pass the selected event
     this.event_copy = function(event) {
       if (event && event.id) {
         var copy = $.extend(true, {}, event);
 
         delete copy.id;
         delete copy._id;
         delete copy.created;
         delete copy.changed;
         delete copy.recurrence_id;
         delete copy.attachments; // @TODO
 
         $.each(copy.attendees, function (k, v) {
           if (v.role != 'ORGANIZER') {
             v.status = 'NEEDS-ACTION';
           }
         })
 
         event_edit_dialog('new', copy);
       }
     };
 
     // show URL of the given calendar in a dialog box
     this.showurl = function(calendar)
     {
       if (calendar.feedurl) {
         var dialog = $('#calendarurlbox').clone(true).removeClass('uidialog');
 
         if (calendar.caldavurl) {
           $('#caldavurl', dialog).val(calendar.caldavurl);
           $('#calendarcaldavurl', dialog).show();
         }
         else {
           $('#calendarcaldavurl', dialog).hide();
         }
 
         rcmail.simple_dialog(dialog, rcmail.gettext('showurl', 'calendar'), null, {
           open: function() { $('#calfeedurl', dialog).val(calendar.feedurl).select(); },
           cancel_button: 'close'
         });
       }
     };
 
     // show free-busy URL in a dialog box
     this.showfburl = function()
     {
       var dialog = $('#fburlbox').clone(true);
 
       rcmail.simple_dialog(dialog, rcmail.gettext('showfburl', 'calendar'), null, {
         open: function() { $('#fburl', dialog).val(settings.freebusy_url).select(); },
         cancel_button: 'close'
       });
     };
 
     // refresh the calendar view after saving event data
     this.refresh = function(p)
     {
       var source = me.calendars[p.source];
 
       // helper function to update the given fullcalendar view
       function update_view(view, event, source) {
         var existing = view.fullCalendar('clientEvents', event._id);
         if (existing.length) {
           $.extend(existing[0], event);
           view.fullCalendar('updateEvent', existing[0]);
           // remove old recurrence instances
           if (event.recurrence && !event.recurrence_id)
             view.fullCalendar('removeEvents', function(e){ return e._id.indexOf(event._id+'-') == 0; });
         }
         else {
           event.source = view.fullCalendar('getEventSourceById', source.id);  // link with source
           view.fullCalendar('renderEvent', event);
         }
       }
 
       // remove temp events
       fc.fullCalendar('removeEvents', function(e){ return e.temp; });
 
       if (source && (p.refetch || (p.update && !source.active))) {
         // activate event source if new event was added to an invisible calendar
         if (this.quickview_active) {
           // map source to the quickview_sources equivalent
           $.each(this.quickview_sources, function(src) {
             if (src.id == source.id) {
               source = src;
               return false;
             }
           });
         }
         else if (!source.active) {
           source.active = true;
           $('#rcmlical' + source.id + ' input').prop('checked', true);
         }
 
         fc.fullCalendar('refetchEventSources', source.id);
         fetch_counts();
       }
       // add/update single event object
       else if (source && p.update) {
         var event = p.update;
         event.temp = false;
         event.editable = 0;
 
         // update main view
         event.editable = source.editable;
         update_view(fc, event, source);
 
         // update the currently displayed event dialog
         if ($('#eventshow').is(':visible') && me.selected_event && me.selected_event.id == event.id)
           event_show_dialog(event)
       }
       // refetch all calendars
       else if (p.refetch) {
         fc.fullCalendar('refetchEvents');
         fetch_counts();
       }
     };
 
     // modify query parameters for refresh requests
     this.before_refresh = function(query)
     {
       var view = fc.fullCalendar('getView');
 
       query.start = date2unixtime(view.start.toDate());
       query.end = date2unixtime(view.end.toDate());
 
       if (this.search_query)
         query.q = this.search_query;
 
       return query;
     };
 
     // callback from server providing event counts
     this.update_counts = function(p)
     {
       $.each(p.counts, function(cal, count) {
         var li = calendars_list.get_item(cal),
           bubble = $(li).children('.calendar').find('span.count');
 
         if (!bubble.length && count > 0) {
           bubble = $('<span>')
             .addClass('count')
             .appendTo($(li).children('.calendar').first())
         }
 
         if (count > 0) {
           bubble.text(count).show();
         }
         else {
           bubble.text('').hide();
         }
       });
     };
 
     // callback after an iTip message event was imported
     this.itip_message_processed = function(data)
     {
       // remove temporary iTip source
       fc.fullCalendar('removeEventSource', this.calendars['--invitation--itip']);
 
       $('#eventshow:ui-dialog').dialog('close');
       this.selected_event = null;
 
       // refresh destination calendar source
       this.refresh({ source:data.calendar, refetch:true });
 
       this.unlock_saving();
 
       // process 'after_action' in mail task
       if (window.opener && window.opener.rcube_libcalendaring)
         window.opener.rcube_libcalendaring.itip_message_processed(data);
     };
 
     // reload the calendar view by keeping the current date/view selection
     this.reload_view = function()
     {
       var query = { view: fc.fullCalendar('getView').name },
         date = fc.fullCalendar('getDate');
       if (date)
         query.date = date2unixtime(date.toDate());
       rcmail.redirect(rcmail.url('', query));
     }
 
     // update browser location to remember current view
     this.update_state = function()
     {
       var query = { view: current_view },
         date = fc.fullCalendar('getDate');
       if (date)
         query.date = date2unixtime(date.toDate());
 
       if (window.history.replaceState)
         window.history.replaceState({}, document.title, rcmail.url('', query).replace('&_action=', ''));
     };
 
     this.resource_search = resource_search;
     this.reset_resource_search = reset_resource_search;
     this.add_resource2event = add_resource2event;
     this.resource_data_load = resource_data_load;
     this.resource_owner_load = resource_owner_load;
 
 
     /***  event searching  ***/
 
     // execute search
     this.quicksearch = function()
     {
       if (rcmail.gui_objects.qsearchbox) {
         var q = rcmail.gui_objects.qsearchbox.value;
         if (q != '') {
           var id = 'search-'+q;
           var sources = [];
           
           if (me.quickview_active)
             reset_quickview();
           
           if (this._search_message)
             rcmail.hide_message(this._search_message);
           
           $.each(fc.fullCalendar('getEventSources'), function() {
             this.url = this.url.replace(/&q=.+/, '') + '&q=' + urlencode(q);
             me.calendars[this.id].url = this.url;
             sources.push(this.id);
           });
           id += '@'+sources.join(',');
           
           // ignore if query didn't change
           if (this.search_request == id) {
             return;
           }
           // remember current view
           else if (!this.search_request) {
             this.default_view = fc.fullCalendar('getView').name;
           }
           
           this.search_request = id;
           this.search_query = q;
           
           // change to list view
           fc.fullCalendar('changeView', 'list');
 
           // refetch events with new url (if not already triggered by changeView)
           if (!this.is_loading)
             fc.fullCalendar('refetchEvents');
         }
         else  // empty search input equals reset
           this.reset_quicksearch();
       }
     };
 
     // reset search and get back to normal event listing
     this.reset_quicksearch = function()
     {
       $(rcmail.gui_objects.qsearchbox).val('');
 
       if (this._search_message)
         rcmail.hide_message(this._search_message);
 
       if (this.search_request) {
         $.each(fc.fullCalendar('getEventSources'), function() {
           this.url = this.url.replace(/&q=.+/, '');
           me.calendars[this.id].url = this.url;
         });
 
         this.search_request = this.search_query = null;
 
         fc.fullCalendar('refetchEvents');
       }
     };
 
     // callback if all sources have been fetched from server
     this.events_loaded = function()
     {
       if (this.search_request && !fc.fullCalendar('clientEvents').length) {
         this._search_message = rcmail.display_message(rcmail.gettext('searchnoresults', 'calendar'), 'notice');
       }
     };
 
     // adjust calendar view size
     this.view_resize = function()
     {
       var footer = fc.fullCalendar('getView').name == 'list' ? $('#agendaoptions').outerHeight() : 0;
       fc.fullCalendar('option', 'height', $('#calendar').height() - footer);
     };
 
     // mark the given calendar folder as selected
     this.select_calendar = function(id, nolistupdate)
     {
       if (!nolistupdate)
         calendars_list.select(id);
 
       // trigger event hook
       rcmail.triggerEvent('selectfolder', { folder:id, prefix:'rcmlical' });
 
       this.selected_calendar = id;
 
       rcmail.update_state({source: id});
       rcmail.enable_command('addevent', this.calendars[id] && this.calendars[id].editable);
     };
 
     // register the given calendar to the current view
     var add_calendar_source = function(cal)
     {
       var color, brightness, select, id = cal.id;
 
       me.calendars[id] = $.extend({
         url: rcmail.url('calendar/load_events', { source: id }),
         className: ['fc-event-cal-' + id],
         id: id
       }, cal);
 
       // choose black text color when background is bright, white otherwise
       if (color = settings.event_coloring % 2  ? '' : '#' + cal.color) {
         me.calendars[id].color = color;
         me.calendars[id].textColor = 'white';
 
         if (/^#([a-f0-9]{2})([a-f0-9]{2})([a-f0-9]{2})$/i.test(color)) {
           // use information about brightness calculation found at
           // http://javascriptrules.com/2009/08/05/css-color-brightness-contrast-using-javascript/
           brightness = (parseInt(RegExp.$1, 16) * 299 + parseInt(RegExp.$2, 16) * 587 + parseInt(RegExp.$3, 16) * 114) / 1000;
           if (brightness > 125)
             me.calendars[id].textColor = '#222';
         }
       }
 
       if (fc && (cal.active || cal.subscribed)) {
         if (cal.active)
           fc.fullCalendar('addEventSource', me.calendars[id]);
 
         var submit = { id: id, active: cal.active ? 1 : 0 };
         if (cal.subscribed !== undefined)
             submit.permanent = cal.subscribed ? 1 : 0;
         rcmail.http_post('calendar', { action:'subscribe', c:submit });
       }
 
       // insert to #calendar-select options if writeable
       select = $('#edit-calendar');
       if (fc && me.has_permission(cal, 'i') && select.length && !select.find('option[value="'+id+'"]').length) {
         $('<option>').attr('value', id).html(cal.name).appendTo(select);
       }
     }
 
     // fetch counts for some calendars from the server
     var fetch_counts = function()
     {
       if (count_sources.length) {
         setTimeout(function() {
           rcmail.http_request('calendar/count', { source:count_sources });
         }, 500);
       }
     };
 
     this.init_calendars = function(refresh)
     {
       var id, cal, active;
 
       for (id in rcmail.env.calendars) {
         cal = rcmail.env.calendars[id];
         active = cal.active || false;
 
         if (!refresh) {
           add_calendar_source(cal);
 
           // check active calendars
           $('#rcmlical'+id+' > .calendar input').prop('checked', active);
 
           if (active) {
             event_sources.push(this.calendars[id]);
           }
           if (cal.counts) {
             count_sources.push(id);
           }
         }
 
         if (cal.editable && (!this.selected_calendar || refresh)) {
           this.selected_calendar = id;
           if (refresh) {
             this.select_calendar(id);
             refresh = false;
           }
         }
       }
     };
 
 
     /***  startup code  ***/
 
     // initialize treelist widget that controls the calendars list
     var widget_class = window.kolab_folderlist || rcube_treelist_widget;
     calendars_list = new widget_class(rcmail.gui_objects.calendarslist, {
       id_prefix: 'rcmlical',
       selectable: true,
       save_state: true,
       keyboard: false,
       searchbox: '#calendarlistsearch',
       search_action: 'calendar/calendar',
       search_sources: [ 'folders', 'users' ],
       search_title: rcmail.gettext('calsearchresults','calendar')
     });
     calendars_list.addEventListener('select', function(node) {
       if (node && node.id && me.calendars[node.id]) {
         me.select_calendar(node.id, true);
         rcmail.enable_command('calendar-edit', 'calendar-showurl', 'calendar-showfburl', true);
         rcmail.enable_command('calendar-delete', me.calendars[node.id].editable);
         rcmail.enable_command('calendar-remove', me.calendars[node.id] && me.calendars[node.id].removable);
       }
     });
     calendars_list.addEventListener('insert-item', function(p) {
       var cal = p.data;
       if (cal && cal.id) {
         add_calendar_source(cal);
 
         // add css classes related to this calendar to document
         if (cal.css) {
           $('<style type="text/css"></style>')
             .html(cal.css)
             .appendTo('head');
         }
       }
     });
     calendars_list.addEventListener('subscribe', function(p) {
       var cal;
       if ((cal = me.calendars[p.id])) {
         cal.subscribed = p.subscribed || false;
         rcmail.http_post('calendar', { action:'subscribe', c:{ id:p.id, active:cal.active?1:0, permanent:cal.subscribed?1:0 } });
       }
     });
     calendars_list.addEventListener('remove', function(p) {
       if (me.calendars[p.id] && me.calendars[p.id].removable) {
         me.calendar_remove(me.calendars[p.id]);
       }
     });
     calendars_list.addEventListener('search-complete', function(data) {
       if (data.length)
         rcmail.display_message(rcmail.gettext('nrcalendarsfound','calendar').replace('$nr', data.length), 'voice');
       else
         rcmail.display_message(rcmail.gettext('nocalendarsfound','calendar'), 'notice');
     });
     calendars_list.addEventListener('click-item', function(event) {
       // handle clicks on quickview icon: temprarily add this source and open in quickview
       if ($(event.target).hasClass('quickview') && event.data) {
         if (!me.calendars[event.data.id]) {
           event.data.readonly = true;
           event.data.active = false;
           event.data.subscribed = false;
           add_calendar_source(event.data);
         }
         me.quickview(event.data.id, event.shiftKey || event.metaKey || event.ctrlKey);
         return false;
       }
     });
 
     // init (delegate) event handler on calendar list checkboxes
     $(rcmail.gui_objects.calendarslist).on('click', 'input[type=checkbox]', function(e) {
       e.stopPropagation();
 
       if (me.quickview_active) {
         this.checked = !this.checked;
         return false;
       }
 
       var id = this.value;
       if (me.calendars[id]) {  // add or remove event source on click
         var action;
         if (this.checked) {
           action = 'addEventSource';
           me.calendars[id].active = true;
         }
         else {
           action = 'removeEventSource';
           me.calendars[id].active = false;
         }
 
         // adjust checked state of original list item
         if (calendars_list.is_search()) {
           calendars_list.container.find('input[value="'+id+'"]').prop('checked', this.checked);
         }
 
         // add/remove event source
         fc.fullCalendar(action, me.calendars[id]);
         rcmail.http_post('calendar', { action:'subscribe', c:{ id:id, active:me.calendars[id].active?1:0 } });
       }
     })
     .on('keypress', 'input[type=checkbox]', function(e) {
         // select calendar on <Enter>
         if (e.keyCode == 13) {
             calendars_list.select(this.value);
             return rcube_event.cancel(e);
         }
     })
     // init (delegate) event handler on quickview links
     .on('click', 'a.quickview', function(e) {
       var id = $(this).closest('li').attr('id').replace(/^rcmlical/, '');
 
       if (calendars_list.is_search())
         id = id.replace(/--xsR$/, '');
 
       if (me.calendars[id])
         me.quickview(id, e.shiftKey || e.metaKey || e.ctrlKey);
 
       if (!rcube_event.is_keyboard(e) && this.blur)
         this.blur();
 
       e.stopPropagation();
       return false;
     });
 
     // register dbl-click handler to open calendar edit dialog
     $(rcmail.gui_objects.calendarslist).on('dblclick', ':not(.virtual) > .calname', function(e){
       var id = $(this).closest('li').attr('id').replace(/^rcmlical/, '');
       me.calendar_edit_dialog(me.calendars[id]);
     });
 
     // Make Elastic checkboxes pretty
     if (window.UI && UI.pretty_checkbox) {
       $(rcmail.gui_objects.calendarslist).find('input[type=checkbox]').each(function() {
         UI.pretty_checkbox($(this).addClass('flex-checkbox'));
       });
       calendars_list.addEventListener('add-item', function(prop) {
         UI.pretty_checkbox($(prop.li).find('input').addClass('flex-checkbox'));
       });
     }
 
     // create list of event sources AKA calendars
     this.init_calendars();
 
     // select default calendar
     if (rcmail.env.source && this.calendars[rcmail.env.source])
       this.selected_calendar = rcmail.env.source;
     else if (settings.default_calendar && this.calendars[settings.default_calendar] && this.calendars[settings.default_calendar].editable)
       this.selected_calendar = settings.default_calendar;
 
     if (this.selected_calendar)
       this.select_calendar(this.selected_calendar);
 
     var viewdate = new Date();
     if (rcmail.env.date)
       viewdate.setTime(fromunixtime(rcmail.env.date));
 
     // add source with iTip event data for rendering
     if (rcmail.env.itip_events && rcmail.env.itip_events.length) {
       me.calendars['--invitation--itip'] = {
         events: rcmail.env.itip_events,
         className: ['fc-event-cal---invitation--itip'],
         color: '#fff',
         textColor: '#333',
         editable: false,
         rights: 'lrs',
         attendees: true
       };
       event_sources.push(me.calendars['--invitation--itip']);
     }
 
     // initalize the fullCalendar plugin
     var fc = $('#calendar').fullCalendar($.extend({}, fullcalendar_defaults, {
       header: {
         right: 'prev,next today',
         center: 'title',
         left: 'agendaDay,agendaWeek,month,list'
       },
       defaultDate: viewdate,
       height: $('#calendar').height(),
       eventSources: event_sources,
       selectable: true,
       selectHelper: false,
       loading: function(isLoading) {
         me.is_loading = isLoading;
         this._rc_loading = rcmail.set_busy(isLoading, me.search_request ? 'searching' : 'loading', this._rc_loading);
         // trigger callback (using timeout, otherwise clientEvents is always empty)
         if (!isLoading)
           setTimeout(function() { me.events_loaded(); }, 20);
       },
       // callback for date range selection
       select: function(start, end, e, view) {
         var range_select = (start.hasTime() || start != end)
         if (dialog_check(e) && range_select)
           event_edit_dialog('new', { start:start, end:end, allDay:!start.hasTime(), calendar:me.selected_calendar });
         if (range_select || ignore_click)
           view.calendar.unselect();
       },
       // callback for clicks in all-day box
       dayClick: function(date, e, view) {
         var now = new Date().getTime();
         if (now - day_clicked_ts < 400 && day_clicked == date.toDate().getTime()) {  // emulate double-click on day
           var enddate = new Date();
           if (date.hasTime())
             enddate.setTime(date.toDate().getTime() + DAY_MS - 60000);
           return event_edit_dialog('new', { start:date, end:enddate, allDay:!date.hasTime(), calendar:me.selected_calendar });
         }
 
         if (!ignore_click) {
           view.calendar.gotoDate(date);
           if (day_clicked && new Date(day_clicked).getMonth() != date.toDate().getMonth())
             view.calendar.select(date, date);
         }
         day_clicked = date.toDate().getTime();
         day_clicked_ts = now;
       },
       // callback when an event was dragged and finally dropped
       eventDrop: function(event, delta, revertFunc) {
         if (!event.end || event.end.diff(event.start) < 0) {
           if (event.allDay)
             event.end = moment(event.start).hour(13).minute(0).second(0);
           else
             event.end = moment(event.start).add(2, 'hours');
         }
         else if (event.allDay) {
           event.end.subtract(1, 'days').hour(13);
         }
 
         if (event.allDay)
           event.start.hour(12);
 
         // send move request to server
         var data = {
           id: event.id,
           calendar: event.calendar,
           start: date2servertime(event.start),
           end: date2servertime(event.end),
           allDay: event.allDay?1:0
         };
 
         update_event_confirm('move', event, data);
       },
       // callback for event resizing
       eventResize: function(event, delta) {
         // sanitize event dates
         if (event.allDay) {
           event.start.hours(12);
           event.end.hour(13).subtract(1, 'days');
         }
 
         // send resize request to server
         var data = {
           id: event.id,
           calendar: event.calendar,
           start: date2servertime(event.start),
           end: date2servertime(event.end),
           allDay: event.allDay?1:0
         };
 
         update_event_confirm('resize', event, data);
       },
       viewRender: function(view, element) {
         $('#agendaoptions')[view.name == 'list' ? 'show' : 'hide']();
         if (minical) {
           window.setTimeout(function(){ minical.datepicker('setDate', fc.fullCalendar('getDate').toDate()); }, exec_deferred);
           if (view.name != current_view)
             me.view_resize();
           current_view = view.name;
           me.update_state();
         }
 
         if (view.name == 'list') {
           var viewStart = moment(view.start);
 
           $('#calendar .fc-prev-button').off('click').on('click', function() {
             fc.fullCalendar('gotoDate', viewStart.subtract(settings.agenda_range, 'days'));
           });
           $('#calendar .fc-next-button').off('click').on('click', function() {
             fc.fullCalendar('gotoDate', viewStart.add(settings.agenda_range, 'days'));
           });
         }
       },
       eventAfterAllRender: function(view) {
         if (view.name == 'list') {
           // Fix colspan of headers after we added Location column
           fc.find('tr.fc-list-heading > td').attr('colspan', 4);
         }
       }
     }));
 
     // if start date is changed, shift end date according to initial duration
     var shift_enddate = function(dateText) {
       var newstart = me.parse_datetime('0', dateText);
       var newend = new Date(newstart.getTime() + $('#edit-startdate').data('duration') * 1000);
       $('#edit-enddate').val(format_date(newend, me.settings.date_format));
       event_times_changed();
     };
 
     // Set as calculateWeek to determine the week of the year based on the ISO 8601 definition.
     // Uses the default $.datepicker.iso8601Week() function but takes firstDay setting into account.
     // This is a temporary fix until http://bugs.jqueryui.com/ticket/8420 is resolved.
     var iso8601Week = me.datepicker_settings.calculateWeek = function(date) {
       var mondayOffset = Math.abs(1 - me.datepicker_settings.firstDay);
       return $.datepicker.iso8601Week(new Date(date.getTime() + mondayOffset * 86400000));
     };
 
     var minical;
     var init_calendar_ui = function()
     {
       var pretty_select = function(elem) {
         // for Elastic
         if (window.UI && UI.pretty_select) {
           $(elem).addClass('form-control custom-select').each(function() { UI.pretty_select(this); });
         }
       };
 
       // initialize small calendar widget using jQuery UI datepicker
       minical = $('#datepicker').datepicker($.extend(me.datepicker_settings, {
         inline: true,
         changeMonth: true,
         changeYear: true,
         onSelect: function(dateText, inst) {
           ignore_click = true;
           var d = minical.datepicker('getDate');
           fc.fullCalendar('gotoDate', d)
           fc.fullCalendar('select', d, d);
           setTimeout(function() { pretty_select($('select', minical)); }, 25);
         },
         onChangeMonthYear: function(year, month, inst) {
           minical.data('year', year).data('month', month);
           setTimeout(function() { pretty_select($('select', minical)); }, 25);
         },
         beforeShowDay: function(date) {
           // TODO: this pretty_select() calls should be implemented in a different way
           setTimeout(function() { pretty_select($('select', minical)); }, 25);
 
           var view = fc.fullCalendar('getView'),
             dt = moment(date).format('YYYYMMDD'),
             active = view.start && view.start.format('YYYYMMDD') <= dt && view.end.format('YYYYMMDD') > dt;
 
           return [ true, (active ? 'ui-datepicker-activerange ui-datepicker-active-' + view.name : ''), ''];
         }
       })) // set event handler for clicks on calendar week cell of the datepicker widget
         .on('click', 'td.ui-datepicker-week-col', function(e) {
           var cell = $(e.target);
           if (e.target.tagName == 'TD') {
             var base_date = minical.datepicker('getDate');
             if (minical.data('month'))
               base_date.setMonth(minical.data('month')-1);
             if (minical.data('year'))
               base_date.setYear(minical.data('year'));
             base_date.setHours(12);
             base_date.setDate(base_date.getDate() - ((base_date.getDay() + 6) % 7) + me.datepicker_settings.firstDay);
             var base_kw = iso8601Week(base_date),
               target_kw = parseInt(cell.html()),
               wdiff = target_kw - base_kw;
             if (wdiff > 10)  // year jump
               base_date.setYear(base_date.getFullYear() - 1);
             else if (wdiff < -10)
               base_date.setYear(base_date.getFullYear() + 1);
             // select monday of the chosen calendar week
             var day_off = base_date.getDay() - me.datepicker_settings.firstDay,
               date = new Date(base_date.getTime() - day_off * DAY_MS + wdiff * 7 * DAY_MS);
 
             fc.fullCalendar('changeView', 'agendaWeek', date);
             minical.datepicker('setDate', date);
             setTimeout(function() { pretty_select($('select', minical)); }, 25);
           }
         });
 
       minical.find('.ui-datepicker-inline').attr('aria-labelledby', 'aria-label-minical');
 
       if (rcmail.env.date) {
         var viewdate = new Date();
         viewdate.setTime(fromunixtime(rcmail.env.date));
         minical.datepicker('setDate', viewdate);
       }
 
       // init event dialog
       var tab_change = function(event, ui) {
           // newPanel.selector for jQuery-UI 1.10, newPanel.attr('id') for jQuery-UI 1.12, href for Bootstrap tabs
           var tab = (ui ? String(ui.newPanel.selector || ui.newPanel.attr('id')) : $(event.target).attr('href'))
             .replace(/^#?event-panel-/, '').replace(/s$/, '');
           var has_real_attendee = function(attendees) {
               for (var i=0; i < (attendees ? attendees.length : 0); i++) {
                 if (attendees[i].cutype != 'RESOURCE')
                   return true;
               }
             };
 
           if (tab == 'attendee' || tab == 'resource') {
             if (!rcube_event.is_keyboard(event))
               $('#edit-'+tab+'-name').select();
             // update free-busy status if needed
             if (freebusy_ui.needsupdate && me.selected_event)
               update_freebusy_status(me.selected_event);
             // add current user as organizer if non added yet
             if (tab == 'attendee' && !has_real_attendee(event_attendees)) {
               add_attendee($.extend({ role:'ORGANIZER' }, settings.identity));
               $('#edit-attendees-form .attendees-invitebox').show();
             }
           }
 
           // reset autocompletion on tab change (#3389)
           rcmail.ksearch_blur();
 
           // display recurrence warning in recurrence tab only
           if (tab == 'recurrence')
             $('#edit-recurrence-frequency').change();
           else
             $('#edit-recurrence-syncstart').hide();
       };
 
       $('#eventedit:not([data-notabs])').tabs({activate: tab_change});  // Larry
       $('#eventedit a.nav-link').on('show.bs.tab', tab_change);         // Elastic
 
       $('#edit-enddate').datepicker(me.datepicker_settings);
       $('#edit-startdate').datepicker(me.datepicker_settings).datepicker('option', 'onSelect', shift_enddate).change(function(){ shift_enddate(this.value); });
       $('#edit-enddate').datepicker('option', 'onSelect', event_times_changed).change(event_times_changed);
       $('#edit-allday').click(function(){ $('#edit-starttime, #edit-endtime')[(this.checked?'hide':'show')](); event_times_changed(); });
 
       // configure drop-down menu on time input fields based on jquery UI autocomplete
       $('#edit-starttime, #edit-endtime').each(function() {
         me.init_time_autocomplete(this, {
           container: '#eventedit',
           change: event_times_changed
         });
       });
 
       // adjust end time when changing start
       $('#edit-starttime').change(function(e) {
         var dstart = $('#edit-startdate'),
           newstart = me.parse_datetime(this.value, dstart.val()),
           newend = new Date(newstart.getTime() + dstart.data('duration') * 1000);
         $('#edit-endtime').val(format_date(newend, me.settings.time_format));
         $('#edit-enddate').val(format_date(newend, me.settings.date_format));
         event_times_changed();
       });
 
       // register events on alarms and recurrence fields
       me.init_alarms_edit('#edit-alarms');
       me.init_recurrence_edit('#eventedit');
 
       // reload free-busy status when changing the organizer identity
       $('#eventedit').on('change', '#edit-identities-list', function(e) {
         var email = settings.identities[$(this).val()],
           icon = $(this).closest('tr').find('.availability > *');
 
         if (email && icon.length) {
           icon.attr('data-email', email);
           check_freebusy_status(icon, email, me.selected_event);
         }
       });
 
       $('#event-export-startdate').datepicker(me.datepicker_settings);
 
       // init attendees autocompletion
       var ac_props;
       // parallel autocompletion
       if (rcmail.env.autocomplete_threads > 0) {
         ac_props = {
           threads: rcmail.env.autocomplete_threads,
           sources: rcmail.env.autocomplete_sources
         };
       }
       rcmail.init_address_input_events($('#edit-attendee-name'), ac_props);
       rcmail.addEventListener('autocomplete_insert', function(e) {
         var cutype, success = false;
         if (e.field.name == 'participant') {
           cutype = e.data && e.data.type == 'group' && e.result_type == 'person' ? 'GROUP' : 'INDIVIDUAL';
           success = add_attendees(e.insert, { role:'REQ-PARTICIPANT', status:'NEEDS-ACTION', cutype:cutype });
         }
         else if (e.field.name == 'resource' && e.data && e.data.email) {
           success = add_attendee($.extend(e.data, { role:'REQ-PARTICIPANT', status:'NEEDS-ACTION', cutype:'RESOURCE' }));
         }
         if (e.field && success) {
           e.field.value = '';
         }
       });
 
       $('#edit-attendee-add').click(function(){
         var input = $('#edit-attendee-name');
         rcmail.ksearch_blur();
         if (add_attendees(input.val(), { role:'REQ-PARTICIPANT', status:'NEEDS-ACTION', cutype:'INDIVIDUAL' })) {
           input.val('');
         }
       });
 
       rcmail.init_address_input_events($('#edit-resource-name'), { action:'calendar/resources-autocomplete' });
 
       $('#edit-resource-add').click(function(){
         var input = $('#edit-resource-name');
         rcmail.ksearch_blur();
         if (add_attendees(input.val(), { role:'REQ-PARTICIPANT', status:'NEEDS-ACTION', cutype:'RESOURCE' })) {
           input.val('');
         }
       });
 
       $('#edit-resource-find').click(function(){
         event_resources_dialog();
         return false;
       });
 
       $('#resource-content a.nav-link').on('click', function() {
         e.preventDefault();
         $(this).tab('show');
       });
 
       // handle change of "send invitations" checkbox
       $('#edit-attendees-invite').change(function() {
         $('#edit-attendees-donotify,input.edit-attendee-reply').prop('checked', this.checked);
         // hide/show comment field
         $('#eventedit .attendees-commentbox')[this.checked ? 'show' : 'hide']();
       });
 
       // delegate change event to "send invitations" checkbox
       $('#edit-attendees-donotify').change(function() {
         $('#edit-attendees-invite').click();
         return false;
       });
 
       $('#edit-attendee-schedule').click(function(){
         event_freebusy_dialog();
       });
 
       $('#schedule-freebusy-prev').html('&#9668;').button().click(function(){ render_freebusy_grid(-1); });
       $('#schedule-freebusy-next').html('&#9658;').button().click(function(){ render_freebusy_grid(1); }); // FIXME .parent().buttonset();
 
       $('#schedule-find-prev').button().click(function(){ freebusy_find_slot(-1); });
       $('#schedule-find-next').button().click(function(){ freebusy_find_slot(1); });
 
       $('#schedule-freebusy-workinghours').click(function(){
         freebusy_ui.workinhoursonly = this.checked;
         $('#workinghourscss').remove();
         if (this.checked)
           $('<style type="text/css" id="workinghourscss"> td.offhours { opacity:0.3; filter:alpha(opacity=30) } </style>').appendTo('head');
       });
 
       $('#event-rsvp input.button').click(function(e) {
         event_rsvp(this)
       });
 
       $('#eventedit input.edit-recurring-savemode').change(function(e) {
         var sel = $('input.edit-recurring-savemode:checked').val(),
           disabled = sel == 'current' || sel == 'future';
         $('#event-panel-recurrence input, #event-panel-recurrence select, #event-panel-attachments input').prop('disabled', disabled);
         $('#event-panel-recurrence, #event-panel-attachments')[(disabled?'addClass':'removeClass')]('disabled');
       })
 
       $('#eventshow .changersvp').click(function(e) {
         var d = $('#eventshow'),
           record = $(this).closest('.event-line,.form-group'),
           h = d.height() - record.height();
 
         record.toggle();
         $('#event-rsvp').slideDown(300, function() {
           me.dialog_resize(d.get(0), h + $(this).outerHeight());
           if (this.scrollIntoView)
             this.scrollIntoView(false);
         });
         return false;
       })
 
       // register click handler for message links
       $('#edit-event-links, #event-links').on('click', 'li a.messagelink', function(e) {
         rcmail.open_window(this.href);
         if (!rcube_event.is_keyboard(e) && this.blur)
           this.blur();
         return false;
       });
 
       // register click handler for message delete buttons
       $('#edit-event-links').on('click', 'li a.delete', function(e) {
           remove_link(e.target);
           return false;
       });
 
       $('#agenda-listrange').change(function(e){
         settings.agenda_range = parseInt($(this).val());
         fc.fullCalendar('changeView', 'list');
         // TODO: save new settings in prefs
       }).val(settings.agenda_range);
 
       // hide event dialog when clicking somewhere into document
       $(document).bind('mousedown', dialog_check);
 
       rcmail.set_busy(false, 'loading', ui_loading);
     }
 
     // initialize more UI elements (deferred)
     window.setTimeout(init_calendar_ui, exec_deferred);
 
     // fetch counts for some calendars
     fetch_counts();
 
     // Save-as-event dialog content
     if (rcmail.env.action == 'dialog-ui') {
       var date = new Date(), event = {allDay: false, calendar: me.selected_calendar};
 
       date.setHours(date.getHours()+1);
       date.setMinutes(0);
 
       var end = new Date(date.getTime());
       end.setHours(date.getHours()+1);
 
       event.start = date;
       event.end = end;
 
       // exec deferred because it must be after init_calendar_ui
       window.setTimeout(function() {
         event_edit_dialog('new', $.extend(event, rcmail.env.event_prop));
       }, exec_deferred);
 
       rcmail.register_command('event-save', function() { rcmail.env.event_save_func(); }, true);
       rcmail.addEventListener('plugin.unlock_saving', function(status) {
         me.unlock_saving();
         if (status)
           window.parent.kolab_event_dialog_element.dialog('destroy');
       });
     }
 } // end rcube_calendar class
 
 
 // Update layout after initialization
 // In devel mode we have to wait until all styles are applied by less
 if (rcmail.env.devel_mode && window.less) {
   less.pageLoadFinished.then(function() { $(window).resize(); });
 }
 
 /* calendar plugin initialization */
 window.rcmail && rcmail.addEventListener('init', function(evt) {
   // let's go
   var cal = new rcube_calendar_ui($.extend(rcmail.env.calendar_settings, rcmail.env.libcal_settings));
 
   if (rcmail.env.action == 'dialog-ui') {
     return;
   }
 
   // configure toolbar buttons
   rcmail.register_command('addevent', function(){ cal.add_event(); });
   rcmail.register_command('print', function(){ cal.print_calendars(); }, true);
 
   // configure list operations
   rcmail.register_command('calendar-create', function(){ cal.calendar_edit_dialog(null); }, true);
   rcmail.register_command('calendar-edit', function(){ cal.calendar_edit_dialog(cal.calendars[cal.selected_calendar]); }, false);
   rcmail.register_command('calendar-remove', function(){ cal.calendar_remove(cal.calendars[cal.selected_calendar]); }, false);
   rcmail.register_command('calendar-delete', function(){ cal.calendar_delete(cal.calendars[cal.selected_calendar]); }, false);
   rcmail.register_command('events-import', function(){ cal.import_events(cal.calendars[cal.selected_calendar]); }, true);
   rcmail.register_command('calendar-showurl', function(){ cal.showurl(cal.calendars[cal.selected_calendar]); }, false);
   rcmail.register_command('calendar-showfburl', function(){ cal.showfburl(); }, false);
   rcmail.register_command('event-download', function(){ cal.event_download(cal.selected_event); }, true);
   rcmail.register_command('event-sendbymail', function(p, obj, e){ cal.event_sendbymail(cal.selected_event, e); }, true);
   rcmail.register_command('event-copy', function(){ cal.event_copy(cal.selected_event); }, true);
   rcmail.register_command('event-history', function(p, obj, e){ cal.event_history_dialog(cal.selected_event); }, false);
 
   // search and export events
   rcmail.register_command('export', function(){ cal.export_events(cal.calendars[cal.selected_calendar]); }, true);
   rcmail.register_command('search', function(){ cal.quicksearch(); }, true);
   rcmail.register_command('reset-search', function(){ cal.reset_quicksearch(); }, true);
 
   // resource invitation dialog
   rcmail.register_command('search-resource', function(){ cal.resource_search(); }, true);
   rcmail.register_command('reset-resource-search', function(){ cal.reset_resource_search(); }, true);
   rcmail.register_command('add-resource', function(){ cal.add_resource2event(); }, false);
 
   // register callback commands
   rcmail.addEventListener('plugin.refresh_source', function(data) { cal.calendar_refresh_source(data); });
   rcmail.addEventListener('plugin.destroy_source', function(p){ cal.calendar_destroy_source(p.id); });
   rcmail.addEventListener('plugin.unlock_saving', function(p){ cal.unlock_saving(); });
   rcmail.addEventListener('plugin.refresh_calendar', function(p){ cal.refresh(p); });
   rcmail.addEventListener('plugin.import_success', function(p){ cal.import_success(p); });
   rcmail.addEventListener('plugin.import_error', function(p){ cal.import_error(p); });
   rcmail.addEventListener('plugin.update_counts', function(p){ cal.update_counts(p); });
   rcmail.addEventListener('plugin.reload_view', function(p){ cal.reload_view(p); });
   rcmail.addEventListener('plugin.resource_data', function(p){ cal.resource_data_load(p); });
   rcmail.addEventListener('plugin.resource_owner', function(p){ cal.resource_owner_load(p); });
   rcmail.addEventListener('plugin.render_event_changelog', function(data){ cal.render_event_changelog(data); });
   rcmail.addEventListener('plugin.event_show_diff', function(data){ cal.event_show_diff(data); });
   rcmail.addEventListener('plugin.close_history_dialog', function(data){ cal.close_history_dialog(); });
   rcmail.addEventListener('plugin.event_show_revision', function(data){ cal.event_show_dialog(data, null, true); });
   rcmail.addEventListener('plugin.itip_message_processed', function(data){ cal.itip_message_processed(data); });
   rcmail.addEventListener('requestrefresh', function(q){ return cal.before_refresh(q); });
 
   $(window).resize(function(e) {
     // check target due to bugs in jquery
     // http://bugs.jqueryui.com/ticket/7514
     // http://bugs.jquery.com/ticket/9841
     if (e.target == window) {
       cal.view_resize();
 
       // In Elastic append the datepicker back to sidebar/dialog when resizing
       // the window from tablet/phone to desktop and vice-versa
       var dp = $('#datepicker'), in_dialog = dp.is('.ui-dialog-content'), width = $(window).width();
       if (in_dialog && width > 768) {
         if (dp.is(':visible')) {
           dp.dialog('close');
         }
         dp.height('auto').removeClass('ui-dialog-content ui-widget-content')
           .data('dialog-parent', dp.closest('.ui-dialog'))
           .appendTo('#layout > div.sidebar');
       }
       else if (!in_dialog && dp.length && width <= 768 && dp.data('dialog-parent')) {
         dp.addClass('ui-dialog-content ui-widget-content')
           .insertAfter(dp.data('dialog-parent').find('.ui-dialog-titlebar'));
       }
     }
   }).resize();
 
   // show calendars list when ready
   $('#calendars').css('visibility', 'inherit');
 
   // show toolbar
   $('#toolbar').show();
 
   // Elastic mods
   if ($('#calendar').data('elastic-mode')) {
     var selector = $('<div class="btn-group btn-group-toggle" role="group">').appendTo('.fc-header-toolbar > .fc-left'),
         nav = $('<div class="btn-group btn-group-toggle" role="group">').appendTo('.fc-header-toolbar > .fc-right');
 
     $('.fc-header-toolbar > .fc-left button').each(function() {
       var new_btn, cl = 'btn btn-secondary', btn = $(this),
         activate = function(button) {
           selector.children('.active').removeClass('active');
           $(button).addClass('active');
         };
 
       if (btn.is('.fc-state-active')) {
         cl += ' active';
       }
 
       new_btn = $('<button>').attr({'class': cl, type: 'button'}).text(btn.text())
         .appendTo(selector)
         .on('click', function() {
           activate(this);
           btn.click();
         });
 
       if (window.MutationObserver) {
         // handle button active state changes
         new MutationObserver(function() { if (btn.is('.fc-state-active')) activate(new_btn); }).observe(this, {attributes: true});
       }
     });
 
     $.each(['prev', 'today', 'next'], function() {
       var btn = $('.fc-header-toolbar > .fc-right').find('.fc-' + this + '-button');
       $('<button>').attr({'class': 'btn btn-secondary ' + this, type: 'button'})
         .text(btn.text()).appendTo(nav).on('click', function() { btn.click(); });
     });
 
     $('#timezone-display').appendTo($('.fc-header-toolbar > .fc-center')).removeClass('hidden');
     $('#agendaoptions').detach().insertAfter('.fc-header-toolbar');
 
     $('.content-frame-navigation a.button.date').appendTo('.content > .searchbar');
 
     // Mobile header title
     if (window.MutationObserver) {
       var title = $('.fc-header-toolbar > .fc-center h2'),
         mobile_header = $('#layout > .content > .header > .header-title'),
         callback = function() {
           var text = title.text();
           mobile_header.html('').append([
             $('<span class="title">').text(text),
             $('<span class="tz">').text($('#timezone-display').text())
           ]);
         };
 
       // update the header when something changes on the calendar title
       new MutationObserver(callback).observe(title[0], {childList: true, subtree: true});
       // initialize the header
       callback();
     }
 
     window.calendar_datepicker = function() {
       $('#datepicker').dialog({
         modal: true,
         title: rcmail.gettext('calendar.selectdate'),
         buttons: [{
           text: rcmail.gettext('close', 'calendar'),
           'class': 'cancel',
           click: function() { $(this).dialog('close'); }
         }],
         width: 400,
         height: 520
       });
     }
   }
 });