diff --git a/plugins/kolab_files/kolab_files.js b/plugins/kolab_files/kolab_files.js
index 81a618f8..a1e02c04 100644
--- a/plugins/kolab_files/kolab_files.js
+++ b/plugins/kolab_files/kolab_files.js
@@ -1,2276 +1,2329 @@
 /**
  * Kolab files plugin
  *
  * @author Aleksander Machniak <machniak@kolabsys.com>
  *
  * @licstart  The following is the entire license notice for the
  * JavaScript code in this file.
  *
  * Copyright (C) 2011, 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.
  */
 
 window.rcmail && window.files_api && rcmail.addEventListener('init', function() {
   if (rcmail.task == 'mail') {
     // mail compose
     if (rcmail.env.action == 'compose') {
       var elem = $('#compose-attachments > div'),
         input = $('<input class="button" type="button">')
           .attr('tabindex', $('input', elem).attr('tabindex') || 0)
           .val(rcmail.gettext('kolab_files.fromcloud'))
           .click(function() { kolab_files_selector_dialog(); })
           .appendTo(elem);
 
       if (rcmail.gui_objects.filelist) {
         rcmail.file_list = new rcube_list_widget(rcmail.gui_objects.filelist, {
           multiselect: true,
           keyboard: true,
           column_movable: false,
           dblclick_time: rcmail.dblclick_time
         });
         rcmail.file_list.addEventListener('select', function(o) { kolab_files_list_select(o); })
           .addEventListener('listupdate', function(e) { rcmail.triggerEvent('listupdate', e); });
 
         rcmail.enable_command('files-sort', 'files-search', 'files-search-reset', true);
 
         rcmail.file_list.init();
         kolab_files_list_coltypes();
       }
 
       // register some commands to skip warning message on compose page
       $.merge(rcmail.env.compose_commands, ['files-list', 'files-sort', 'files-search', 'files-search-reset']);
     }
     // mail preview
     else if (rcmail.env.action == 'show' || rcmail.env.action == 'preview') {
       var attachment_list = $('#attachment-list');
 
       if ($('li', attachment_list).length) {
         var link = $('<a href="#" class="button filesaveall">')
           .text(rcmail.gettext('kolab_files.saveall'))
           .click(function() { kolab_directory_selector_dialog(); })
           .insertAfter(attachment_list);
       }
 
       rcmail.addEventListener('menu-open', kolab_files_attach_menu_open);
       rcmail.enable_command('folder-create', true);
     }
     // attachment preview
     else if (rcmail.env.action == 'get') {
       rcmail.enable_command('folder-create', true);
     }
 
     kolab_files_init();
   }
   else if (rcmail.task == 'files') {
     if (rcmail.gui_objects.filelist) {
       rcmail.file_list = new rcube_list_widget(rcmail.gui_objects.filelist, {
         multiselect: true,
         draggable: true,
         keyboard: true,
         column_movable: rcmail.env.col_movable,
         dblclick_time: rcmail.dblclick_time
       });
-/*
-      rcmail.file_list.row_init = function(o){ kolab_files_init_file_row(o); };
-      rcmail.file_list.addEventListener('dblclick', function(o){ p.msglist_dbl_click(o); });
-      rcmail.file_list.addEventListener('click', function(o){ p.msglist_click(o); });
-      rcmail.file_list.addEventListener('keypress', function(o){ p.msglist_keypress(o); });
-      rcmail.file_list.addEventListener('dragstart', function(o){ p.drag_start(o); });
-      rcmail.file_list.addEventListener('dragmove', function(e){ p.drag_move(e); });
-*/
+
       rcmail.file_list.addEventListener('dblclick', function(o) { kolab_files_list_dblclick(o); })
         .addEventListener('select', function(o) { kolab_files_list_select(o); })
         .addEventListener('keypress', function(o) { kolab_files_list_keypress(o); })
+        .addEventListener('dragstart', function(e) { kolab_files_drag_start(e); })
+        .addEventListener('dragmove', function(e) { kolab_files_drag_move(e); })
         .addEventListener('dragend', function(e) { kolab_files_drag_end(e); })
         .addEventListener('column_replace', function(e) { kolab_files_set_coltypes(e); })
         .addEventListener('listupdate', function(e) { rcmail.triggerEvent('listupdate', e); });
 
       rcmail.enable_command('menu-open', 'menu-save', 'files-sort', 'files-search', 'files-search-reset', 'folder-create', true);
 
       rcmail.file_list.init();
       kolab_files_list_coltypes();
       kolab_files_drag_drop_init($(rcmail.gui_objects.filelist).parents('.droptarget'));
     }
 
     // "one file only" commands
     rcmail.env.file_commands = ['files-get'];
     // "one or more file" commands
     rcmail.env.file_commands_all = ['files-delete', 'files-move', 'files-copy'];
 
     kolab_files_init();
 
     if (rcmail.env.action == 'open') {
       rcmail.enable_command('files-get', 'files-delete', rcmail.env.file);
     }
     else {
       file_api.folder_list();
       file_api.browser_capabilities_check();
       rcmail.enable_command('folder-mount', rcmail.env.external_sources);
     }
   }
 });
 
 
 /**********************************************************/
 /*********          Shared functionality         **********/
 /**********************************************************/
 
 // Initializes API object
 function kolab_files_init()
 {
   if (window.file_api)
     return;
 
   // Initialize application object (don't change var name!)
   file_api = $.extend(new files_api(), new kolab_files_ui());
 
   file_api.set_env({
     token: kolab_files_token(),
     url: rcmail.env.files_url,
     sort_col: 'name',
     sort_reverse: false,
     search_threads: rcmail.env.search_threads,
     resources_dir: rcmail.assets_path('program/resources'),
     supported_mimetypes: rcmail.env.file_mimetypes
   });
 
   file_api.translations = rcmail.labels;
 };
 
 // returns API authorization token
 function kolab_files_token()
 {
   // consider the token from parent window more reliable (fresher) than in framed window
   // it's because keep-alive is not requested in frames
   return window.parent && parent.rcmail && parent.rcmail.env.files_token ? parent.rcmail.env.files_token : rcmail.env.files_token;
 };
 
 // folder selection dialog
 function kolab_directory_selector_dialog(id)
 {
   var dialog = $('#files-dialog'),
     input = $('#file-save-as-input'),
     form = $('#file-save-as'),
     list = $('#folderlistbox'),
     buttons = {}, label = 'saveto',
     win = window, fn;
 
   // attachment is specified
   if (id) {
     var attach = $('#attach' + id + '> a').first(),
       filename = attach.attr('title');
 
     if (!filename) {
       attach = attach.clone();
       $('.attachment-size', attach).remove();
       filename = attach.text();
     }
 
     form.show();
     dialog.addClass('saveas');
     input.val(filename);
   }
   // attachment preview page
   else if (rcmail.env.action == 'get') {
     id = rcmail.env.part;
     form.show();
     dialog.addClass('saveas');
     input.val(rcmail.env.filename);
   }
   else {
     form.hide();
     dialog.removeClass('saveas');
     label = 'saveall';
   }
 
   $('#foldercreatelink').attr('tabindex', 0);
 
   buttons[rcmail.gettext('kolab_files.save')] = function () {
     var lock = rcmail.set_busy(true, 'saving'),
       request = {
         act: 'save-file',
         source: rcmail.env.mailbox,
         uid: rcmail.env.uid,
         dest: file_api.env.folder
       };
 
     if (id) {
       request.id = id;
       request.name = input.val();
     }
 
     rcmail.http_post('plugin.kolab_files', request, lock);
     kolab_dialog_close(this);
   };
 
   buttons[rcmail.gettext('kolab_files.cancel')] = function () {
     kolab_dialog_close(this);
   };
 
   if (!rcmail.env.folders_loaded) {
     fn = function() {
       file_api.folder_list();
       rcmail.env.folders_loaded = true;
     };
   }
 
   // show dialog window
   kolab_dialog_show(dialog, {
     title: rcmail.gettext('kolab_files.' + label),
     buttons: buttons,
     button_classes: ['mainaction'],
     minWidth: 250,
     minHeight: 300,
     height: 350,
     width: 300
   }, fn);
 
   // "enable" folder creation when dialog is displayed in parent window
   if (rcmail.is_framed() && !parent.rcmail.folder_create) {
     parent.rcmail.enable_command('folder-create', true);
     parent.rcmail.folder_create = function() {
       win.kolab_files_folder_create_dialog();
     };
   }
 };
 
 // file selection dialog
 function kolab_files_selector_dialog()
 {
   var dialog = $('#files-compose-dialog'), buttons = {};
 
   buttons[rcmail.gettext('kolab_files.attachsel')] = function () {
     var list = [];
     $('#filelist tr.selected').each(function() {
       list.push($(this).data('file'));
     });
 
     kolab_dialog_close(this);
 
     if (list.length) {
       // display upload indicator and cancel button
       var content = '<span>' + rcmail.get_label('kolab_files.attaching') + '</span>',
         id = new Date().getTime();
 
       rcmail.add2attachment_list(id, {name:'', html:content, classname:'uploading', complete:false});
 
       // send request
       rcmail.http_post('plugin.kolab_files', {
         act: 'attach-file',
         files: list,
         id: rcmail.env.compose_id,
         uploadid: id
       });
     }
   };
 
   buttons[rcmail.gettext('kolab_files.cancel')] = function () {
     kolab_dialog_close(this);
   };
 
   // show dialog window
   kolab_dialog_show(dialog, {
     title: rcmail.gettext('kolab_files.selectfiles'),
     buttons: buttons,
     button_classes: ['mainaction'],
     minWidth: 500,
     minHeight: 300,
     width: 700,
     height: 500
   });
 
   if (!rcmail.env.files_loaded) {
     file_api.folder_list();
     rcmail.env.files_loaded = true;
   }
   else {
     rcmail.file_list.clear_selection();
   }
 };
 
 function kolab_files_attach_menu_open(p)
 {
   if (!p || !p.props || p.props.menu != 'attachmentmenu')
     return;
 
   var id = p.props.id;
 
   $('#attachmenusaveas').unbind('click').attr('onclick', '').click(function(e) {
     return kolab_directory_selector_dialog(id);
   });
 };
 
 // folder creation dialog
 function kolab_files_folder_create_dialog()
 {
   var dialog = $('#files-folder-create-dialog'),
     buttons = {},
     select = $('select[name="parent"]', dialog).html(''),
     input = $('input[name="name"]', dialog).val('');
 
   buttons[rcmail.gettext('kolab_files.create')] = function () {
     var folder = '', name = input.val(), parent = select.val();
 
     if (!name)
       return;
 
     if (parent)
       folder = parent + file_api.env.directory_separator;
 
     folder += name;
 
     file_api.folder_create(folder);
     kolab_dialog_close(this);
   };
 
   buttons[rcmail.gettext('kolab_files.cancel')] = function () {
     kolab_dialog_close(this);
   };
 
   // show dialog window
   kolab_dialog_show(dialog, {
     title: rcmail.gettext('kolab_files.foldercreate'),
     buttons: buttons,
     button_classes: ['mainaction']
   });
 
   // Fix submitting form with Enter
   $('form', dialog).submit(kolab_dialog_submit_handler);
 
   // build parent selector
   select.append($('<option>').val('').text('---'));
   $.each(file_api.env.folders, function(i, f) {
     var n, option = $('<option>'), name = escapeHTML(f.name);
 
     for (n=0; n<f.depth; n++)
       name = '&nbsp;&nbsp;&nbsp;' + name;
 
     option.val(i).html(name).appendTo(select);
 
     if (i == file_api.env.folder)
       option.attr('selected', true);
   });
 };
 
 // folder edit dialog
 function kolab_files_folder_edit_dialog()
 {
   var dialog = $('#files-folder-edit-dialog'),
     buttons = {}, options = [],
     separator = file_api.env.directory_separator,
     arr = file_api.env.folder.split(separator),
     folder = arr.pop(),
     path = arr.join(separator),
     select = $('select[name="parent"]', dialog).html(''),
     input = $('input[name="name"]', dialog).val(folder);
 
   buttons[rcmail.gettext('kolab_files.save')] = function () {
     var folder = '', name = input.val(), parent = select.val();
 
     if (!name)
       return;
 
     if (parent)
       folder = parent + separator;
 
     folder += name;
 
     file_api.folder_rename(file_api.env.folder, folder);
     kolab_dialog_close(this);
   };
 
   buttons[rcmail.gettext('kolab_files.cancel')] = function () {
     kolab_dialog_close(this);
   };
 
   // show dialog window
   kolab_dialog_show(dialog, {
     title: rcmail.gettext('kolab_files.folderedit'),
     buttons: buttons,
     button_classes: ['mainaction']
   });
 
   // Fix submitting form with Enter
   $('form', dialog).submit(kolab_dialog_submit_handler);
 
   // build parent selector
   options.push($('<option>').val('').text('---'));
   $.each(file_api.env.folders, function(i, f) {
     var n, name = escapeHTML(f.name);
 
     for (n=0; n<f.depth; n++)
       name = '&nbsp;&nbsp;&nbsp;' + name;
 
     options.push($('<option>').val(i).html(name));
   });
 
   select.append(options).val(path);
 };
 
 // folder mounting dialog
 function kolab_files_folder_mount_dialog()
 {
   var args = {buttons: {}, title: rcmail.gettext('kolab_files.foldermount')},
     dialog = $('#files-folder-mount-dialog'),
     input = $('#folder-mount-name').val('');
 
   args.buttons[rcmail.gettext('kolab_files.save')] = function () {
     var args = {}, folder = input.val(),
       driver = $('input[name="driver"]:checked', dialog).val();
 
     if (!folder || !driver)
       return;
 
     args.folder = folder;
     args.driver = driver;
 
     $('#source-' + driver + ' input').each(function() {
       if (this.name.startsWith(driver + '[')) {
         args[this.name.substring(driver.length + 1, this.name.length - 1)] = this.value;
       }
     });
 
     $('.auth-options input', dialog).each(function() {
       args[this.name] = this.type == 'checkbox' && !this.checked ? '' : this.value;
     });
 
     file_api.folder_mount(args);
     kolab_dialog_close(this);
   };
 
   args.buttons[rcmail.gettext('kolab_files.cancel')] = function () {
     kolab_dialog_close(this);
   };
 
   // close folderoption menu
   rcmail.hide_menu('folderoptions');
 
   // initialize drivers list
   if (!rcmail.drivers_list_initialized) {
     rcmail.drivers_list_initialized = true;
 
     $('td.source', dialog).each(function() {
       $(this).click(function() {
         $('td.selected', dialog).removeClass('selected');
         dialog.find('.driverform').hide();
         $(this).addClass('selected').find('.driverform').show();
         $('input[type="radio"]', this).prop('checked', true);
      });
    });
   }
 
   args.button_classes = ['mainaction'];
 
   // show dialog window
   kolab_dialog_show(dialog, args, function() {
     $('td.source:first', dialog).click();
     input.focus();
   });
 };
 
 // file edition dialog
 function kolab_files_file_edit_dialog(file)
 {
   var dialog = $('#files-file-edit-dialog'),
     buttons = {}, name = file_api.file_name(file)
     input = $('input[name="name"]', dialog).val(name);
 
   buttons[rcmail.gettext('kolab_files.save')] = function () {
     var folder = file_api.file_path(file), name = input.val();
 
     if (!name)
       return;
 
     name = folder + file_api.env.directory_separator + name;
 
     // @TODO: now we only update filename
     if (name != file)
       file_api.file_rename(file, name);
     kolab_dialog_close(this);
   };
   buttons[rcmail.gettext('kolab_files.cancel')] = function () {
     kolab_dialog_close(this);
   };
 
   // Fix submitting form with Enter
   $('form', dialog).submit(kolab_dialog_submit_handler);
 
   // show dialog window
   kolab_dialog_show(dialog, {
     title: rcmail.gettext('kolab_files.fileedit'),
     buttons: buttons,
     button_classes: ['mainaction']
   });
 };
 
 function kolab_dialog_show(content, params, onopen)
 {
   params = $.extend({
     modal: true,
     resizable: true,
     closeOnEscape: (!bw.ie6 && !bw.ie7),  // disabled for performance reasons
     minWidth: 400,
     minHeight: 300,
     width: 500,
     height: 400
   }, params || {});
 
   // dialog close handler
   params.close = function(e, ui) {
     var elem, stack = rcmail.dialog_stack;
 
     content.appendTo(document.body).hide();
     $(this).parent().remove(); // remove dialog
 
     // focus previously focused element (guessed)
     stack.pop();
     if (stack.length) {
       elem = stack[stack.length-1].find('input[type!="hidden"]:not(:hidden):first');
       if (!elem.length)
         elem = stack[stack.length-1].parent().find('a[role="button"], .ui-dialog-buttonpane button').first();
     }
 
     (elem && elem.length ? elem : window).focus();
   };
 
   // display it as popup
   var dialog = rcmail.show_popup_dialog('', params.title, params.buttons, params);
 
   content.appendTo(dialog).show().find('input[type!="hidden"]:not(:hidden):first').focus();
 
   if (onopen) onopen(content);
 
   // save dialog reference, to handle focus when closing one of opened dialogs
   if (!rcmail.dialog_stack)
     rcmail.dialog_stack = [];
 
   rcmail.dialog_stack.push(dialog);
 };
 
 // Handle form submit with Enter key, click first dialog button instead
 function kolab_dialog_submit_handler()
 {
   $(this).parents('.ui-dialog').find('.ui-button').first().click();
   return false;
 };
 
 // Hides dialog
 function kolab_dialog_close(dialog)
 {
   (rcmail.is_framed() ? window.parent : window).$(dialog).dialog('close');
 };
 
 // smart upload button
 function kolab_files_upload_input(button)
 {
   var link = $(button),
     file = $('<input>'),
     offset = link.offset();
 
   function move_file_input(e) {
     file.css({top: (e.pageY - offset.top - 10) + 'px', left: (e.pageX - offset.left - 10) + 'px'});
   }
 
   file.attr({name: 'file[]', type: 'file', multiple: 'multiple', size: 5, title: link.attr('title'), tabindex: "-1"})
     .change(function() { rcmail.files_upload('#filesuploadform'); })
     .click(function() { setTimeout(function() { link.mouseleave(); }, 20); })
     // opacity:0 does the trick, display/visibility doesn't work
     .css({opacity: 0, cursor: 'pointer', outline: 'none', position: 'absolute'});
 
   // In FF and IE we need to move the browser file-input's button under the cursor
   // Thanks to the size attribute above we know the length of the input field
   if (bw.mz || bw.ie)
     file.css({marginLeft: '-80px'});
 
   // Note: now, I observe problem with cursor style on FF < 4 only
   // Need position: relative (Bug #2615)
   link.css({overflow: 'hidden', cursor: 'pointer', position: 'relative'})
     .mouseenter(function() { this.__active = true; })
     // place button under the cursor
     .mousemove(function(e) {
       if (rcmail.commands['files-upload'] && this.__active)
         move_file_input(e);
       // move the input away if button is disabled
       else
         $(this).mouseleave();
     })
     .mouseleave(function() {
       file.css({top: '-10000px', left: '-10000px'});
       this.__active = false;
     })
     .attr('onclick', '') // remove default button action
     .click(function(e) {
       // forward click if mouse-enter event was missed
       if (rcmail.commands['files-upload'] && !this.__active) {
         this.__active = true;
         move_file_input(e);
         file.trigger(e);
       }
     })
     .mouseleave() // initially disable/hide input
     .append(file);
 };
 
 
 /***********************************************************/
 /**********          Main functionality           **********/
 /***********************************************************/
 
 // for reordering column array (Konqueror workaround)
 // and for setting some message list global variables
 kolab_files_list_coltypes = function()
 {
   var n, list = rcmail.file_list;
 
   rcmail.env.subject_col = null;
 
   if ((n = $.inArray('name', rcmail.env.coltypes)) >= 0) {
     rcmail.env.subject_col = n;
     list.subject_col = n;
   }
 
   list.init_header();
 };
 
 kolab_files_set_list_options = function(cols, sort_col, sort_order)
 {
   var update = 0, i, idx, name, newcols = [], oldcols = rcmail.env.coltypes;
 
   if (sort_col === undefined)
     sort_col = rcmail.env.sort_col;
   if (!sort_order)
     sort_order = rcmail.env.sort_order;
 
   if (rcmail.env.sort_col != sort_col || rcmail.env.sort_order != sort_order) {
     update = 1;
     rcmail.set_list_sorting(sort_col, sort_order);
   }
 
   if (cols && cols.length) {
     // make sure new columns are added at the end of the list
     for (i=0; i<oldcols.length; i++) {
       name = oldcols[i];
       idx = $.inArray(name, cols);
       if (idx != -1) {
         newcols.push(name);
         delete cols[idx];
       }
     }
     for (i=0; i<cols.length; i++)
       if (cols[i])
         newcols.push(cols[i]);
 
     if (newcols.join() != oldcols.join()) {
       update += 2;
       oldcols = newcols;
     }
   }
 
   if (update == 1)
     rcmail.command('files-list', {sort: sort_col, reverse: sort_order == 'DESC'});
   else if (update) {
     rcmail.http_post('files/prefs', {
       kolab_files_list_cols: oldcols,
       kolab_files_sort_col: sort_col,
       kolab_files_sort_order: sort_order
       }, rcmail.set_busy(true, 'loading'));
   }
 };
 
 kolab_files_set_coltypes = function(list)
 {
   var i, found, name, cols = list.list.tHead.rows[0].cells;
 
   rcmail.env.coltypes = [];
 
   for (i=0; i<cols.length; i++)
     if (cols[i].id && cols[i].id.match(/^rcm/)) {
       name = cols[i].id.replace(/^rcm/, '');
       rcmail.env.coltypes.push(name);
     }
 
 //  if ((found = $.inArray('name', rcmail.env.coltypes)) >= 0)
 //    rcmail.env.subject_col = found;
   rcmail.env.subject_col = list.subject_col;
 
   rcmail.http_post('files/prefs', {kolab_files_list_cols: rcmail.env.coltypes});
 };
 
 kolab_files_list_dblclick = function(list)
 {
   rcmail.command('files-open');
 };
 
 kolab_files_list_select = function(list)
 {
   var selected = list.selection.length;
 
   rcmail.enable_command(rcmail.env.file_commands_all, selected);
   rcmail.enable_command(rcmail.env.file_commands, selected == 1);
 
     // reset all-pages-selection
 //  if (list.selection.length && list.selection.length != list.rowcount)
 //    rcmail.select_all_mode = false;
 
   // enable files-
   if (selected == 1) {
     // get file mimetype
     var type = $('tr.selected', list.list).data('type');
     rcmail.env.viewer = file_api.file_type_supported(type);
   }
   else
     rcmail.env.viewer = 0;
 /*
     ) {
 //      caps = this.browser_capabilities().join();
       href = '?' + $.param({_task: 'files', _action: 'open', file: file, viewer: viewer == 2 ? 1 : 0});
       var win = window.open(href, rcmail.html_identifier('rcubefile'+file));
       if (win)
         setTimeout(function() { win.focus(); }, 10);
     }
 */
   rcmail.enable_command('files-open', rcmail.env.viewer);
 };
 
 kolab_files_list_keypress = function(list)
 {
   if (list.modkey == CONTROL_KEY)
     return;
 
   if (list.key_pressed == list.ENTER_KEY)
     rcmail.command('files-open');
   else if (list.key_pressed == list.DELETE_KEY || list.key_pressed == list.BACKSPACE_KEY)
     rcmail.command('files-delete');
 };
 
+kolab_files_drag_start = function(e)
+{
+  rcmail.env.drag_target = null;
+
+  if (rcmail.folder_list)
+    rcmail.folder_list.drag_start();
+};
+
 kolab_files_drag_end = function(e)
 {
-  var folder = $('#files-folder-list li.droptarget').removeClass('droptarget');
+  if (rcmail.folder_list) {
+    rcmail.folder_list.drag_end();
 
-  if (folder.length) {
-    folder = folder.data('folder');
+    if (rcmail.env.drag_target) {
+      var modkey = rcube_event.get_modifier(e),
+        menu = rcmail.gui_objects.file_dragmenu;
 
-    var modkey = rcube_event.get_modifier(e),
-      menu = rcmail.gui_objects.file_dragmenu;
+      rcmail.file_list.draglayer.hide();
 
-    if (menu && modkey == SHIFT_KEY && rcmail.commands['files-copy']) {
-      var pos = rcube_event.get_mouse_pos(e);
-      rcmail.env.drag_target = folder;
-      $(menu).css({top: (pos.y-10)+'px', left: (pos.x-10)+'px'}).show();
-      return;
+      if (menu && modkey == SHIFT_KEY && rcmail.commands['files-copy']) {
+        var pos = rcube_event.get_mouse_pos(e);
+        $(menu).css({top: (pos.y-10)+'px', left: (pos.x-10)+'px'}).show();
+        return;
+      }
+
+      rcmail.command('files-move', rcmail.env.drag_target);
     }
+  }
+};
+
+kolab_files_drag_move = function(e)
+{
+  if (rcmail.folder_list) {
+    var mouse = rcube_event.get_mouse_pos(e);
 
-    rcmail.command('files-move', folder);
+    rcmail.env.drag_target = rcmail.folder_list.intersects(mouse, true);
   }
 };
 
 kolab_files_drag_menu_action = function(command)
 {
   var menu = rcmail.gui_objects.file_dragmenu;
 
   if (menu)
     $(menu).hide();
 
   rcmail.command(command, rcmail.env.drag_target);
 };
 
 kolab_files_selected = function()
 {
   var files = [];
   $.each(rcmail.file_list.get_selection(), function(i, v) {
     var name, row = $('#rcmrow'+v);
 
     if (row.length == 1 && (name = row.data('file')))
       files.push(name);
   });
 
   return files;
 };
 
 kolab_files_frame_load = function(frame)
 {
   var win = frame.contentWindow;
 
   rcmail.file_editor = win.file_editor && win.file_editor.editable ? win.file_editor : null;
 
   if (rcmail.file_editor)
     rcmail.enable_command('files-edit', true);
 
   rcmail.enable_command('files-print', (rcmail.file_editor && rcmail.file_editor.printable) ||
     (rcmail.env.file_data && /^image\//i.test(rcmail.env.file_data.type)));
 
   // detect Print button and check if it can be accessed
   try {
     if ($('#fileframe').contents().find('#print').length)
       rcmail.enable_command('files-print', true);
   }
   catch(e) {};
 };
 
 // activate html5 file drop feature (if browser supports it)
 kolab_files_drag_drop_init = function(container)
 {
   if (!window.FormData && !(window.XMLHttpRequest && XMLHttpRequest.prototype && XMLHttpRequest.prototype.sendAsBinary)) {
     return;
   }
 
   if (!container.length)
     return;
 
   $(document.body).bind('dragover dragleave drop', function(e) {
     if (!file_api.env.folder)
       return;
 
     e.preventDefault();
     container[e.type == 'dragover' ? 'addClass' : 'removeClass']('active');
   });
 
   container.bind('dragover dragleave', function(e) {
     return kolab_files_drag_hover(e);
   })
   container.children('div').bind('dragover dragleave', function(e) {
     return kolab_files_drag_hover(e);
   })
   container.get(0).addEventListener('drop', function(e) {
       // abort event and reset UI
       kolab_files_drag_hover(e);
       return file_api.file_drop(e);
     }, false);
 };
 
 // handler for drag/drop on element
 kolab_files_drag_hover = function(e)
 {
   if (!file_api.env.folder)
     return;
 
   e.preventDefault();
   e.stopPropagation();
 
   var elem = $(e.target);
 
   if (!elem.hasClass('droptarget'))
     elem = elem.parents('.droptarget');
 
   elem[e.type == 'dragover' ? 'addClass' : 'removeClass']('hover');
 };
 
 // returns localized file size
 kolab_files_file_size = function(size)
 {
   var i, units = ['GB', 'MB', 'KB', 'B'];
 
   size = file_api.file_size(size);
 
   for (i = 0; i < units.length; i++)
     if (size.toUpperCase().indexOf(units[i]) > 0)
       return size.replace(units[i], rcmail.gettext(units[i]));
 
   return size;
 };
 
 kolab_files_progress_str = function(param)
 {
   var current, total = file_api.file_size(param.total).toUpperCase();
 
   if (total.indexOf('GB') > 0)
     current = parseFloat(param.current/1073741824).toFixed(1);
   else if (total.indexOf('MB') > 0)
     current = parseFloat(param.current/1048576).toFixed(1);
   else if (total.indexOf('KB') > 0)
     current = parseInt(param.current/1024);
   else
     current = param.current;
 
   total = kolab_files_file_size(param.total);
 
   return rcmail.gettext('uploadprogress')
     .replace(/\$percent/, param.percent + '%')
     .replace(/\$current/, current)
     .replace(/\$total/, total);
 };
 
 
 /***********************************************************/
 /**********              Commands                 **********/
 /***********************************************************/
 
 rcube_webmail.prototype.files_sort = function(props)
 {
   var params = {},
     sort_order = this.env.sort_order,
     sort_col = !this.env.disabled_sort_col ? props : this.env.sort_col;
 
   if (!this.env.disabled_sort_order)
     sort_order = this.env.sort_col == sort_col && sort_order == 'ASC' ? 'DESC' : 'ASC';
 
   // set table header and update env
   this.set_list_sorting(sort_col, sort_order);
 
   this.http_post('files/prefs', {kolab_files_sort_col: sort_col, kolab_files_sort_order: sort_order});
 
   params.sort = sort_col;
   params.reverse = sort_order == 'DESC';
 
   this.command('files-list', params);
 };
 
 rcube_webmail.prototype.files_search = function()
 {
   var value = $(this.gui_objects.filesearchbox).val();
 
   if (value)
     file_api.file_search(value, $('#search_all_folders').is(':checked'));
   else
     file_api.file_search_reset();
 };
 
 rcube_webmail.prototype.files_search_reset = function()
 {
   $(this.gui_objects.filesearchbox).val('');
 
   file_api.file_search_reset();
 };
 
 rcube_webmail.prototype.files_folder_delete = function()
 {
   if (confirm(this.get_label('kolab_files.folderdeleteconfirm')))
     file_api.folder_delete(file_api.env.folder);
 };
 
 rcube_webmail.prototype.files_delete = function()
 {
   if (!confirm(this.get_label('kolab_files.filedeleteconfirm')))
     return;
 
   var files = this.env.file ? [this.env.file] : kolab_files_selected();
   file_api.file_delete(files);
 };
 
 rcube_webmail.prototype.files_move = function(folder)
 {
   var files = kolab_files_selected();
   file_api.file_move(files, folder);
 };
 
 rcube_webmail.prototype.files_copy = function(folder)
 {
   var files = kolab_files_selected();
   file_api.file_copy(files, folder);
 };
 
 rcube_webmail.prototype.files_upload = function(form)
 {
   if (form)
     file_api.file_upload(form);
 };
 
 rcube_webmail.prototype.files_list = function(param)
 {
   // just rcmail wrapper, to handle command busy states
   file_api.file_list(param);
 }
 
 rcube_webmail.prototype.files_list_update = function(head)
 {
   var list = this.file_list;
 
   list.clear();
   $('thead', list.fixed_header ? list.fixed_header : list.list).html(head);
   kolab_files_list_coltypes();
   file_api.file_list();
 };
 
 rcube_webmail.prototype.files_get = function()
 {
   var files = this.env.file ? [this.env.file] : kolab_files_selected();
 
   if (files.length == 1)
     file_api.file_get(files[0], {'force-download': true});
 };
 
 rcube_webmail.prototype.files_open = function()
 {
   var files = kolab_files_selected();
 
   if (files.length == 1)
     file_api.file_open(files[0], rcmail.env.viewer);
 };
 
 // enable file editor
 rcube_webmail.prototype.files_edit = function()
 {
   if (this.file_editor) {
     this.file_editor.enable();
     this.enable_command('files-save', true);
   }
 };
 
 rcube_webmail.prototype.files_save = function()
 {
   if (!this.file_editor)
     return;
 
   // binary files like ODF need to be updated using FormData
   if (this.file_editor.getContentCallback) {
     if (!file_api.file_uploader_support())
       return;
 
     file_api.req = file_api.set_busy(true, 'saving');
 //    this.file_editor.disable();
     this.file_editor.getContentCallback(function(content, filename) {
       file_api.file_uploader([content], {
         action: 'file_update',
         params: {file: rcmail.env.file, info: 1, token: file_api.env.token},
         response_handler: 'file_save_response',
         fieldname: 'content',
         single: true
       });
     });
 
     return;
   }
 
   var content = this.file_editor.getContent();
 
   file_api.file_save(this.env.file, content);
 };
 
 rcube_webmail.prototype.files_print = function()
 {
   if (this.file_editor && this.file_editor.printable)
     this.file_editor.print();
   else if (/^image\//i.test(this.env.file_data.type)) {
     var frame = $('#fileframe').get(0),
       win = frame ? frame.contentWindow : null;
 
     if (win) {
       win.focus();
       win.print();
     }
   }
   else {
     // e.g. Print button in PDF viewer
     try {
       $('#fileframe').contents().find('#print').click();
     }
     catch(e) {};
   }
 };
 
 rcube_webmail.prototype.files_set_quota = function(p)
 {
   if (p.total && window.file_api) {
     p.used *= 1024;
     p.total *= 1024;
     p.title = file_api.file_size(p.used) + ' / ' + file_api.file_size(p.total)
         + ' (' + p.percent + '%)';
   }
 
   p.type = this.env.quota_type;
 
   this.set_quota(p);
 };
 
 rcube_webmail.prototype.folder_create = function()
 {
   kolab_files_folder_create_dialog();
 };
 
 rcube_webmail.prototype.folder_rename = function()
 {
   kolab_files_folder_edit_dialog();
 };
 
 rcube_webmail.prototype.folder_mount = function()
 {
   kolab_files_folder_mount_dialog();
 };
 
 
 /**********************************************************/
 /*********          Files API handler            **********/
 /**********************************************************/
 
 function kolab_files_ui()
 {
   this.requests = {};
   this.uploads = [];
 
 /*
   // Called on "session expired" session
   this.logout = function(response) {};
 
   // called when a request timed out
   this.request_timed_out = function() {};
 
   // called on start of the request
   this.set_request_time = function() {};
 
   // called on request response
   this.update_request_time = function() {};
 */
   // set state
   this.set_busy = function(a, message)
   {
     if (this.req)
       rcmail.hide_message(this.req);
 
     return rcmail.set_busy(a, message);
   };
 
   // displays error message
   this.display_message = function(label, type)
   {
     return rcmail.display_message(this.t(label), type);
   };
 
   this.http_error = function(request, status, err)
   {
     rcmail.http_error(request, status, err);
   };
 
   // folders list request
   this.folder_list = function()
   {
     this.req = this.set_busy(true, 'loading');
     this.request('folder_list', {}, 'folder_list_response');
   };
 
   // folder list response handler
   this.folder_list_response = function(response)
   {
     if (!this.response(response))
       return;
 
-    var first, elem = $('#files-folder-list'),
-      list = $('<ul class="listing"></ul>'),
+    var first, rows = [],
+      elem = $('#files-folder-list'),
+      list = $('<ul class="treelist listing folderlist"></ul>'),
       collections = !rcmail.env.action.match(/^(preview|show)$/) ? ['audio', 'video', 'image', 'document'] : [];
 
     // try parent window if the list element does not exist
     // i.e. called from dialog in parent window
     if (!elem.length && window.parent && parent.rcmail) {
       elem = $('#files-folder-list', window.parent.document.body);
     }
 
     elem.html('').append(list);
 
     this.env.folders = this.folder_list_parse(response.result && response.result.list ? response.result.list : response.result);
 
     $.each(this.env.folders, function(i, f) {
-      list.append(file_api.folder_list_row(i, f));
-      if (!first)
-        first = i;
+      var row;
+      if (row = file_api.folder_list_row(i, f)) {
+        if (!first)
+          first = i;
+        rows.push(row);
+      }
     });
 
     // add virtual collections
     $.each(collections, function(i, n) {
       var row = $('<li class="mailbox collection ' + n + '"></li>');
 
-      row.attr({id: 'folder-collection-' + n, tabindex: 0})
-        .append($('<span class="name"></span>').text(rcmail.gettext('kolab_files.collection_' + n)))
-        .click(function() { file_api.folder_select(n, true); });
+      row.attr('id', 'rcmli' + rcmail.html_identifier_encode('folder-collection-' + n))
+        .append($('<a class="name"></a>').text(rcmail.gettext('kolab_files.collection_' + n)))
 
-      list.append(row);
+      rows.push(row);
     });
 
+    list.append(rows);
+
+    // init treelist widget
+    rcmail.folder_list = new rcube_treelist_widget(list, {
+        selectable: true,
+        id_prefix: 'rcmli',
+        parent_focus: true,
+        id_encode: rcmail.html_identifier_encode,
+        id_decode: rcmail.html_identifier_decode,
+        check_droptarget: function(node) {
+          return !node.virtual
+            && node.id != file_api.env.folder
+            && $.inArray('collection', node.classes) == -1;
+        }
+    });
+
+    rcmail.folder_list
+      .addEventListener('collapse', function(node) { file_api.folder_collapsed(node); })
+      .addEventListener('expand', function(node) { file_api.folder_collapsed(node); })
+      .addEventListener('beforeselect', function(node) { return !rcmail.busy; })
+      .addEventListener('select', function(node) { file_api.folder_select(node.id); });
+
     // select first folder?
     if (this.env.folder)
-      this.folder_select(this.env.folder);
+      rcmail.folder_list.select(this.env.folder);
     else if (this.env.collection)
-      this.folder_select(this.env.collection, true);
+      rcmail.folder_list.select('folder-collection-' + this.env.collection);
     else if (first)
-      this.folder_select(first);
+      rcmail.folder_list.select(first);
 
     // add tree icons
-    this.folder_list_tree(this.env.folders);
+//    this.folder_list_tree(this.env.folders);
 
     // handle authentication errors on external sources
     this.folder_list_auth_errors(response.result);
   };
 
-  this.folder_select = function(folder, is_collection)
+  this.folder_select = function(folder)
   {
     if (rcmail.busy)
       return;
 
-    var list = $('#files-folder-list > ul');
-
-    // try parent window if the list element does not exist
-    // i.e. called from dialog in parent window
-    if (!list.length && window.parent && parent.rcmail) {
-      list = $('#files-folder-list > ul', window.parent.document.body);
-    }
-
-    $('li.selected', list).removeClass('selected');
+    var is_collection = folder.match(/^folder-collection-/);
 
     rcmail.enable_command('files-list', true);
+    rcmail.enable_command('files-folder-delete', 'folder-rename', 'files-upload', !is_collection);
 
     if (is_collection) {
-      var found = $('#folder-collection-' + folder, list).addClass('selected');
-
-      rcmail.enable_command('files-folder-delete', 'folder-rename', 'files-upload', false);
       this.env.folder = null;
-      rcmail.command('files-list', {collection: folder});
+      rcmail.command('files-list', {collection: folder.replace(/^folder-collection-/, '')});
     }
     else {
-      var found = $('#' + this.env.folders[folder].id, list).addClass('selected');
-
-      rcmail.enable_command('files-folder-delete', 'folder-rename', 'files-upload', true);
       this.env.folder = folder;
       this.env.collection = null;
       rcmail.command('files-list', {folder: folder});
     }
 
     this.quota();
   };
 
   this.folder_unselect = function()
   {
-    var list = $('#files-folder-list > ul');
-    $('li.selected', list).removeClass('selected');
-    rcmail.enable_command('files-folder-delete', 'files-upload', false);
+    rcmail.folder_list.select();
     this.env.folder = null;
     this.env.collection = null;
+    rcmail.enable_command('files-folder-delete', 'files-upload', false);
   };
 
-  this.folder_list_row = function(i, folder)
+  this.folder_collapsed = function(node)
   {
-    var row = $('<li class="mailbox"><span class="branch"></span></li>');
+    var prefname = 'kolab_files_collapsed_folders',
+      old = rcmail.env[prefname],
+      entry = '&' + urlencode(node.id) + '&';
 
-    row.attr('id', folder.id).data('folder', i)
-      .append($('<span class="name"></span>').text(folder.name));
+    if (node.collapsed) {
+      rcmail.env[prefname] = rcmail.env[prefname] + entry;
 
-    if (folder.depth) {
-      $('span.branch', row).width(15 * folder.depth);
-      row.addClass('child');
+      // select the folder if one of its childs is currently selected
+      // don't select if it's virtual (#1488346)
+      if (!node.virtual && this.env.folder && this.env.folder.startsWith(node.id + '/')) {
+        rcmail.folder_list.select(node.id);
+      }
+    }
+    else {
+      rcmail.env[prefname] = rcmail.env[prefname].replace(entry, '');
     }
 
+    if (old !== rcmail.env[prefname] && (!rcmail.file_list || !rcmail.file_list.drag_active))
+      rcmail.command('save-pref', {name: prefname, value: rcmail.env[prefname]});
+  };
+
+  this.folder_list_row = function(i, folder, parent)
+  {
+    var toggle, sublist, collapsed, parent, parent_name,
+      row = $('<li class="mailbox"></li>'),
+      id = 'rcmli' + rcmail.html_identifier_encode(i);
+
+    row.attr('id', id).append($('<a></a>').text(folder.name));
+
     if (folder.virtual)
       row.addClass('virtual');
-    else
-      row.attr('tabindex', 0)
-        .keypress(function(e) { if (e.which == 13 || e.which == 32) file_api.folder_select(i); })
-        .click(function() { file_api.folder_select(i); })
-        .mouseenter(function() {
-          if (rcmail.file_list && rcmail.file_list.drag_active && !$(this).hasClass('selected'))
-            $(this).addClass('droptarget');
-        })
-        .mouseleave(function() {
-          if (rcmail.file_list && rcmail.file_list.drag_active)
-            $(this).removeClass('droptarget');
-        });
 
-    return row;
+    folder.ref = row;
+
+    if (folder.depth) {
+      // find parent folder
+      parent_name = i.replace(/\/[^/]+$/, '');
+      if (!parent)
+        parent = $(this.env.folders[parent_name].ref);
+
+      toggle = $('div.treetoggle', parent);
+      sublist = $('> ul', parent);
+
+      if (!toggle.length) {
+        collapsed = rcmail.env.kolab_files_collapsed_folders.indexOf('&' + urlencode(parent_name) + '&') > -1;
+
+        toggle = $('<div>').attr('class', 'treetoggle' + (collapsed ? ' collapsed' : ' expanded'))
+          .html('&nbsp;').appendTo(parent);
+
+        sublist = $('<ul>').attr({role: 'group'}).appendTo(parent);
+        if (collapsed)
+          sublist.hide();
+      }
+
+      sublist.append(row);
+    }
+    else {
+      return row;
+    }
   };
 
   // folder create request
   this.folder_create = function(folder)
   {
     this.req = this.set_busy(true, 'kolab_files.foldercreating');
     this.request('folder_create', {folder: folder}, 'folder_create_response');
   };
 
   // folder create response handler
   this.folder_create_response = function(response)
   {
     if (!this.response(response))
       return;
 
     this.display_message('kolab_files.foldercreatenotice', 'confirmation');
 
     // refresh folders list
     this.folder_list();
   };
 
   // folder rename request
   this.folder_rename = function(folder, new_name)
   {
     if (folder == new_name)
       return;
 
     this.env.folder_rename = new_name;
     this.req = this.set_busy(true, 'kolab_files.folderupdating');
     this.request('folder_move', {folder: folder, 'new': new_name}, 'folder_rename_response');
   };
 
   // folder create response handler
   this.folder_rename_response = function(response)
   {
     if (!this.response(response))
       return;
 
     this.display_message('kolab_files.folderupdatenotice', 'confirmation');
 
     // refresh folders and files list
     this.env.folder = this.env.folder_rename;
     this.folder_list();
   };
 
   // folder mount (external storage) request
   this.folder_mount = function(data)
   {
     this.req = this.set_busy(true, 'kolab_files.foldermounting');
     this.request('folder_create', data, 'folder_mount_response');
   };
 
   // folder create response handler
   this.folder_mount_response = function(response)
   {
     if (!this.response(response))
       return;
 
     this.display_message('kolab_files.foldermountnotice', 'confirmation');
 
     // refresh folders list
     this.folder_list();
   };
 
   // folder delete request
   this.folder_delete = function(folder)
   {
     this.req = this.set_busy(true, 'kolab_files.folderdeleting');
     this.request('folder_delete', {folder: folder}, 'folder_delete_response');
   };
 
   // folder delete response handler
   this.folder_delete_response = function(response)
   {
     if (!this.response(response))
       return;
 
     this.env.folder = null;
     rcmail.enable_command('files-folder-delete', 'folder-rename', 'files-list', false);
     this.display_message('kolab_files.folderdeletenotice', 'confirmation');
 
     // refresh folders list
     this.folder_list();
     this.quota();
   };
 
   // quota request
   this.quota = function()
   {
     if (rcmail.env.files_quota)
       this.request('quota', {folder: this.env.folder}, 'quota_response');
   };
 
   // quota response handler
   this.quota_response = function(response)
   {
     if (!this.response(response))
       return;
 
     rcmail.files_set_quota(response.result);
   };
 
   this.file_list = function(params)
   {
     if (!rcmail.gui_objects.filelist)
       return;
 
     if (!params)
       params = {};
 
     // reset all pending list requests
     for (i in this.requests) {
       this.requests[i].abort();
       rcmail.hide_message(i);
       delete this.requests[i];
     }
 
     if (params.all_folders) {
       params.collection = null;
       params.folder = null;
       this.folder_unselect();
     }
 
     if (params.collection == undefined)
       params.collection = this.env.collection;
     if (params.folder == undefined)
       params.folder = this.env.folder;
     if (params.sort == undefined)
       params.sort = this.env.sort_col;
     if (params.reverse == undefined)
       params.reverse = this.env.sort_reverse;
     if (params.search == undefined)
       params.search = this.env.search;
 
     this.env.folder = params.folder;
     this.env.collection = params.collection;
     this.env.sort_col = params.sort;
     this.env.sort_reverse = params.reverse;
 
     rcmail.enable_command(rcmail.env.file_commands, false);
     rcmail.enable_command(rcmail.env.file_commands_all, false);
 
     // empty the list
     this.env.file_list = [];
     rcmail.file_list.clear(true);
 
     // request
     if (params.collection || params.all_folders)
       this.file_list_loop(params);
     else if (this.env.folder) {
       params.req_id = this.set_busy(true, 'loading');
       this.requests[params.req_id] = this.request('file_list', params, 'file_list_response');
     }
   };
 
   // file list response handler
   this.file_list_response = function(response)
   {
     if (response.req_id)
       rcmail.hide_message(response.req_id);
 
     if (!this.response(response))
       return;
 
     var i = 0, list = [], table = $('#filelist');
 
     $.each(response.result, function(key, data) {
       var row = file_api.file_list_row(key, data, ++i);
       rcmail.file_list.insert_row(row);
       data.row = row;
       data.filename = key;
       list.push(data);
     });
 
     this.env.file_list = list;
     rcmail.file_list.resize();
   };
 
   // call file_list request for every folder (used for search and virt. collections)
   this.file_list_loop = function(params)
   {
     var i, folders = [], limit = Math.max(this.env.search_threads || 1, 1);
 
     if (params.collection) {
       if (!params.search)
         params.search = {};
       params.search['class'] = params.collection;
       delete params['collection'];
     }
 
     delete params['all_folders'];
 
     $.each(this.env.folders, function(i, f) {
       if (!f.virtual)
         folders.push(i);
     });
 
     this.env.folders_loop = folders;
     this.env.folders_loop_params = params;
     this.env.folders_loop_lock = false;
 
     for (i=0; i<folders.length && i<limit; i++) {
       params.req_id = this.set_busy(true, 'loading');
       params.folder = folders.shift();
       this.requests[params.req_id] = this.request('file_list', params, 'file_list_loop_response');
     }
   };
 
   // file list response handler for loop'ed request
   this.file_list_loop_response = function(response)
   {
     var i, folders = this.env.folders_loop,
       params = this.env.folders_loop_params,
       limit = Math.max(this.env.search_threads || 1, 1),
       valid = this.response(response);
 
     if (response.req_id)
       rcmail.hide_message(response.req_id);
 
     for (i=0; i<folders.length && i<limit; i++) {
       params.req_id = this.set_busy(true, 'loading');
       params.folder = folders.shift();
       this.requests[params.req_id] = this.request('file_list', params, 'file_list_loop_response');
     }
 
     rcmail.file_list.resize();
 
     if (!valid)
       return;
 
     this.file_list_loop_result_add(response.result);
   };
 
   // add files from list request to the table (with sorting)
   this.file_list_loop_result_add = function(result)
   {
     // chack if result (hash-array) is empty
     if (!object_is_empty(result))
       return;
 
     if (this.env.folders_loop_lock) {
       setTimeout(function() { file_api.file_list_loop_result_add(result); }, 100);
       return;
     }
 
     // lock table, other list responses will wait
     this.env.folders_loop_lock = true;
 
     var n, i, len, elem, list = [], rows = [],
       index = this.env.file_list.length,
       table = rcmail.file_list;
 
     for (n=0, len=index; n<len; n++) {
       elem = this.env.file_list[n];
       for (i in result) {
         if (this.sort_compare(elem, result[i]) < 0)
           break;
 
         var row = this.file_list_row(i, result[i], ++index);
         table.insert_row(row, elem.row);
         result[i].row = row;
         result[i].filename = i;
         list.push(result[i]);
         delete result[i];
       }
 
       list.push(elem);
     }
 
     // add the rest of rows
     $.each(result, function(key, data) {
       var row = file_api.file_list_row(key, data, ++index);
       table.insert_row(row);
       result[key].row = row;
       result[key].filename = key;
       list.push(result[key]);
     });
 
     this.env.file_list = list;
     this.env.folders_loop_lock = false;
   };
 
   // sort files list (without API request)
   this.file_list_sort = function(col, reverse)
   {
     var n, len, list = this.env.file_list,
       table = $('#filelist'), tbody = $('<tbody>');
 
     this.env.sort_col = col;
     this.env.sort_reverse = reverse;
 
     if (!list || !list.length)
       return;
 
     // sort the list
     list.sort(function (a, b) {
       return file_api.sort_compare(a, b);
     });
 
     // add rows to the new body
     for (n=0, len=list.length; n<len; n++) {
       tbody.append(list[n].row);
     }
 
     // replace table bodies
     $('tbody', table).replaceWith(tbody);
   };
 
   this.file_list_row = function(file, data, index)
   {
     var c, col, row = '';
 
     for (c in rcmail.env.coltypes) {
       c = rcmail.env.coltypes[c];
       if (c == 'name')
         col = '<td class="name filename ' + this.file_type_class(data.type) + '">'
           + '<span>' + escapeHTML(data.name) + '</span></td>';
       else if (c == 'mtime')
         col = '<td class="mtime">' + data.mtime + '</td>';
       else if (c == 'size')
         col = '<td class="size">' + this.file_size(data.size) + '</td>';
       else if (c == 'options')
         col = '<td class="options"><span></span></td>';
       else
         col = '<td class="' + c + '"></td>';
 
       row += col;
     }
 
     row = $('<tr>')
       .html(row)
       .attr({id: 'rcmrow' + index, 'data-file': file, 'data-type': data.type});
 
     $('td.options > span', row).click(function(e) {
       kolab_files_file_edit_dialog(file);
     });
 
     // collection (or search) lists files from all folders
     // display file name with full path as title
     if (!this.env.folder)
       $('td.name span', row).attr('title', file);
 
     return row.get(0);
   };
 
   this.file_search = function(value, all_folders)
   {
     if (value) {
       this.env.search = {name: value};
       rcmail.command('files-list', {search: this.env.search, all_folders: all_folders});
     }
     else
       this.search_reset();
   };
 
   this.file_search_reset = function()
   {
     if (this.env.search) {
       this.env.search = null;
       rcmail.command('files-list');
     }
   };
 
   this.file_get = function(file, params)
   {
     if (!params)
       params = {};
 
     params.token = this.env.token;
     params.file = file;
 
     rcmail.redirect(this.env.url + this.url('file_get', params));
   };
 
   // file(s) delete request
   this.file_delete = function(files)
   {
     this.req = this.set_busy(true, 'kolab_files.filedeleting');
     this.request('file_delete', {file: files}, 'file_delete_response');
   };
 
   // file(s) delete response handler
   this.file_delete_response = function(response)
   {
     if (!this.response(response))
       return;
 
     var rco, dir, self = this;
 
     this.display_message('kolab_files.filedeletenotice', 'confirmation');
 
     if (rcmail.env.file) {
       rco = rcmail.opener();
       dir = this.file_path(rcmail.env.file);
 
       // check if opener window contains files list, if not we can just close current window
       if (rco && rco.file_list && (opener.file_api.env.folder == dir || !opener.file_api.env.folder))
         self = opener.file_api;
       else
         window.close();
     }
 
     // @TODO: consider list modification "in-place" instead of full reload
     self.file_list();
     self.quota();
 
     if (rcmail.env.file)
       window.close();
   };
 
   // file(s) move request
   this.file_move = function(files, folder)
   {
     if (!files || !files.length || !folder)
       return;
 
     var count = 0, list = {};
 
     $.each(files, function(i, v) {
       var name = folder + file_api.env.directory_separator + file_api.file_name(v);
 
       if (name != v) {
         list[v] = name;
         count++;
       }
     });
 
     if (!count)
       return;
 
     this.req = this.set_busy(true, 'kolab_files.filemoving');
     this.request('file_move', {file: list}, 'file_move_response');
   };
 
   // file(s) move response handler
   this.file_move_response = function(response)
   {
     if (!this.response(response))
       return;
 
     if (response.result && response.result.already_exist && response.result.already_exist.length)
       this.file_move_ask_user(response.result.already_exist, true);
     else {
       this.display_message('kolab_files.filemovenotice', 'confirmation');
       this.file_list();
     }
   };
 
   // file(s) copy request
   this.file_copy = function(files, folder)
   {
     if (!files || !files.length || !folder)
       return;
 
     var count = 0, list = {};
 
     $.each(files, function(i, v) {
       var name = folder + file_api.env.directory_separator + file_api.file_name(v);
 
       if (name != v) {
         list[v] = name;
         count++;
       }
     });
 
     if (!count)
       return;
 
     this.req = this.set_busy(true, 'kolab_files.filecopying');
     this.request('file_copy', {file: list}, 'file_copy_response');
   };
 
   // file(s) copy response handler
   this.file_copy_response = function(response)
   {
     if (!this.response(response))
       return;
 
     if (response.result && response.result.already_exist && response.result.already_exist.length)
       this.file_move_ask_user(response.result.already_exist);
     else {
       this.display_message('kolab_files.filecopynotice', 'confirmation');
       this.quota();
     }
   };
 
   // when file move/copy operation returns file-exists error
   // this displays a dialog where user can decide to skip
   // or overwrite destination file(s)
   this.file_move_ask_user = function(list, move)
   {
     var file = list[0], buttons = {},
       text = rcmail.gettext('kolab_files.filemoveconfirm').replace('$file', file.dst)
       dialog = $('<div></div>');
 
     buttons[rcmail.gettext('kolab_files.fileoverwrite')] = function() {
       var file = list.shift(), f = {},
         action = move ? 'file_move' : 'file_copy';
 
       f[file.src] = file.dst;
       file_api.file_move_ask_list = list;
       file_api.file_move_ask_mode = move;
       dialog.dialog('destroy').remove();
       file_api.req = file_api.set_busy(true, move ? 'kolab_files.filemoving' : 'kolab_files.filecopying');
       file_api.request(action, {file: f, overwrite: 1}, 'file_move_ask_user_response');
     };
 
     if (list.length > 1)
       buttons[rcmail.gettext('kolab_files.fileoverwriteall')] = function() {
         var f = {}, action = move ? 'file_move' : 'file_copy';
 
         $.each(list, function() { f[this.src] = this.dst; });
         dialog.dialog('destroy').remove();
         file_api.req = file_api.set_busy(true, move ? 'kolab_files.filemoving' : 'kolab_files.filecopying');
         file_api.request(action, {file: f, overwrite: 1}, action + '_response');
       };
 
     var skip_func = function() {
       list.shift();
       dialog.dialog('destroy').remove();
 
       if (list.length)
         file_api.file_move_ask_user(list, move);
       else if (move)
         file_api.file_list();
     };
 
     buttons[rcmail.gettext('kolab_files.fileskip')] = skip_func;
 
     if (list.length > 1)
       buttons[rcmail.gettext('kolab_files.fileskipall')] = function() {
       dialog.dialog('destroy').remove();
         if (move)
           file_api.file_list();
       };
 
     // open jquery UI dialog
     kolab_dialog_show(dialog.html(text), {
       close: skip_func,
       buttons: buttons,
       minWidth: 400,
       width: 400
     });
   };
 
   // file move (with overwrite) response handler
   this.file_move_ask_user_response = function(response)
   {
     var move = this.file_move_ask_mode, list = this.file_move_ask_list;
 
     this.response(response);
 
     if (list && list.length)
       this.file_move_ask_user(list, mode);
     else {
       this.display_message('kolab_files.file' + (move ? 'move' : 'copy') + 'notice', 'confirmation');
       if (move)
         this.file_list();
     }
   };
 
   // file(s) rename request
   this.file_rename = function(oldfile, newfile)
   {
     this.req = this.set_busy(true, 'kolab_files.fileupdating');
     this.request('file_move', {file: oldfile, 'new': newfile}, 'file_rename_response');
   };
 
   // file(s) move response handler
   this.file_rename_response = function(response)
   {
     if (!this.response(response))
       return;
 
     // @TODO: we could update metadata instead
     this.file_list();
   };
 
   // file upload request
   this.file_upload = function(form)
   {
     var form = $(form),
       field = $('input[type=file]', form).get(0),
       files = field.files ? field.files.length : field.value ? 1 : 0;
 
     if (!files || !this.file_upload_size_check(field.files))
       return;
 
     // submit form and read server response
     this.file_upload_form(form, 'file_upload', function(event) {
       var doc, response;
       try {
         doc = this.contentDocument ? this.contentDocument : this.contentWindow.document;
         response = doc.body.innerHTML;
         // response may be wrapped in <pre> tag
         if (response.slice(0, 5).toLowerCase() == '<pre>' && response.slice(-6).toLowerCase() == '</pre>') {
           response = doc.body.firstChild.firstChild.nodeValue;
         }
         response = eval('(' + response + ')');
       }
       catch (err) {
         response = {status: 'ERROR'};
       }
 
       file_api.file_upload_progress_stop(event.data.ts);
 
       // refresh the list on upload success
       file_api.file_upload_response(response);
     });
   };
 
   // refresh the list on upload success
   this.file_upload_response = function(response)
   {
     if (this.response_parse(response)) {
        this.file_list();
        this.quota();
     }
   };
 
   // check upload max size
   this.file_upload_size_check = function(files)
   {
     var i, size = 0, maxsize = rcmail.env.files_max_upload;
 
     if (maxsize && files) {
       for (i=0; i < files.length; i++)
         size += files[i].size || files[i].fileSize;
 
       if (size > maxsize) {
         alert(rcmail.get_label('kolab_files.uploadsizeerror').replace('$size', kolab_files_file_size(maxsize)));
         return false;
       }
     }
 
     return true;
   };
 
   // post the given form to a hidden iframe
   this.file_upload_form = function(form, action, onload)
   {
     var ts = new Date().getTime(),
       frame_name = 'fileupload' + ts;
 
     // upload progress support
     if (rcmail.env.files_progress_name) {
       var fname = rcmail.env.files_progress_name,
         field = $('input[name='+fname+']', form);
 
       if (!field.length) {
         field = $('<input>').attr({type: 'hidden', name: fname});
         field.prependTo(form);
       }
 
       field.val(ts);
       this.file_upload_progress(ts, true);
     }
 
     rcmail.display_progress({name: ts});
 
     // have to do it this way for IE
     // otherwise the form will be posted to a new window
     if (document.all) {
       var html = '<iframe id="'+frame_name+'" name="'+frame_name+'"'
         + ' src="' + rcmail.assets_path('program/resources/blank.gif') + '"'
         + ' style="width:0;height:0;visibility:hidden;"></iframe>';
       document.body.insertAdjacentHTML('BeforeEnd', html);
     }
     // for standards-compliant browsers
     else
       $('<iframe>')
         .attr({name: frame_name, id: frame_name})
         .css({border: 'none', width: 0, height: 0, visibility: 'hidden'})
         .appendTo(document.body);
 
     // handle upload errors, parsing iframe content in onload
     $('#'+frame_name).on('load', {ts:ts}, onload);
 
     $(form).attr({
       target: frame_name,
       action: this.env.url + this.url(action, {folder: this.env.folder, token: this.env.token}),
       method: 'POST'
     }).attr(form.encoding ? 'encoding' : 'enctype', 'multipart/form-data')
       .submit();
   };
 
   // handler when files are dropped to a designated area.
   // compose a multipart form data and submit it to the server
   this.file_drop = function(e)
   {
     var files = e.target.files || e.dataTransfer.files;
 
     if (!files || !files.length || !this.file_upload_size_check(files))
       return;
 
     // prepare multipart form data composition
     var ts = new Date().getTime(),
       formdata = window.FormData ? new FormData() : null,
       fieldname = 'file[]',
       boundary = '------multipartformboundary' + (new Date).getTime(),
       dashdash = '--', crlf = '\r\n',
       multipart = dashdash + boundary + crlf;
 
     // inline function to submit the files to the server
     var submit_data = function() {
       var multiple = files.length > 1;
 
       rcmail.display_progress({name: ts});
       if (rcmail.env.files_progress_name)
         file_api.file_upload_progress(ts, true);
 
       // complete multipart content and post request
       multipart += dashdash + boundary + dashdash + crlf;
 
       $.ajax({
         type: 'POST',
         dataType: 'json',
         url: file_api.env.url + file_api.url('file_upload', {folder: file_api.env.folder}),
         contentType: formdata ? false : 'multipart/form-data; boundary=' + boundary,
         processData: false,
         timeout: 0, // disable default timeout set in ajaxSetup()
         data: formdata || multipart,
         headers: {'X-Session-Token': file_api.env.token},
         success: function(data) {
           file_api.file_upload_progress_stop(ts);
           file_api.file_upload_response(data);
         },
         error: function(o, status, err) {
           file_api.file_upload_progress_stop(ts);
           rcmail.http_error(o, status, err);
         },
         xhr: function() {
           var xhr = jQuery.ajaxSettings.xhr();
           if (!formdata && xhr.sendAsBinary)
             xhr.send = xhr.sendAsBinary;
           return xhr;
         }
       });
     };
 
     // upload progress supported (and handler exists)
     // add progress ID to the request - need to be added before files
     if (rcmail.env.files_progress_name) {
       if (formdata)
         formdata.append(rcmail.env.files_progress_name, ts);
       else
         multipart += 'Content-Disposition: form-data; name="' + rcmail.env.files_progress_name + '"'
           + crlf + crlf + ts + crlf + dashdash + boundary + crlf;
     }
 
     // get contents of all dropped files
     var f, j, i = 0, last = files.length - 1;
     for (j = 0; j <= last && (f = files[i]); i++) {
       if (!f.name) f.name = f.fileName;
       if (!f.size) f.size = f.fileSize;
       if (!f.type) f.type = 'application/octet-stream';
 
       // file name contains non-ASCII characters, do UTF8-binary string conversion.
       if (!formdata && /[^\x20-\x7E]/.test(f.name))
         f.name_bin = unescape(encodeURIComponent(f.name));
 
       // do it the easy way with FormData (FF 4+, Chrome 5+, Safari 5+)
       if (formdata) {
         formdata.append(fieldname, f);
         if (j == last)
           return submit_data();
       }
       // use FileReader supporetd by Firefox 3.6
       else if (window.FileReader) {
         var reader = new FileReader();
 
         // closure to pass file properties to async callback function
         reader.onload = (function(file, j) {
           return function(e) {
             multipart += 'Content-Disposition: form-data; name="' + fieldname + '"';
             multipart += '; filename="' + (f.name_bin || file.name) + '"' + crlf;
             multipart += 'Content-Length: ' + file.size + crlf;
             multipart += 'Content-Type: ' + file.type + crlf + crlf;
             multipart += reader.result + crlf;
             multipart += dashdash + boundary + crlf;
 
             if (j == last)  // we're done, submit the data
               return submit_data();
           }
         })(f,j);
         reader.readAsBinaryString(f);
       }
 
       j++;
     }
   };
 
   // upload progress requests
   this.file_upload_progress = function(id, init)
   {
     if (init && id)
       this.uploads[id] = this.env.folder;
 
     setTimeout(function() {
       if (id && file_api.uploads[id])
         file_api.request('upload_progress', {id: id}, 'file_upload_progress_response');
     }, rcmail.env.files_progress_time * 1000);
   };
 
   // upload progress response
   this.file_upload_progress_response = function(response)
   {
     if (!this.response(response))
       return;
 
     var param = response.result;
 
     if (!param.id || !this.uploads[param.id])
       return;
 
     if (param.total) {
       param.name = param.id;
 
       if (!param.done)
         param.text = kolab_files_progress_str(param);
 
       rcmail.display_progress(param);
     }
 
     if (!param.done && param.total)
       this.file_upload_progress(param.id);
     else
       delete this.uploads[param.id];
   };
 
   this.file_upload_progress_stop = function(id)
   {
     if (id) {
       delete this.uploads[id];
       rcmail.display_progress({name: id});
     }
   };
 
   // open file in new window, using file API viewer
   this.file_open = function(file, viewer)
   {
     var href = '?' + $.param({_task: 'files', _action: 'open', file: file, viewer: viewer == 2 ? 1 : 0});
     rcmail.open_window(href, false, true);
   };
 
   // save file
   this.file_save = function(file, content)
   {
     rcmail.enable_command('files-save', false);
     // because we currently can edit only text files
     // and we do not expect them to be very big, we save
     // file in a very simple way, no upload progress, etc.
     this.req = this.set_busy(true, 'saving');
     this.request('file_update', {file: file, content: content, info: 1}, 'file_save_response');
   };
 
   // file save response handler
   this.file_save_response = function(response)
   {
     rcmail.enable_command('files-save', true);
 
     if (!this.response(response))
       return;
 
     // update file properties table
     var table = $('#fileinfobox table'), file = response.result;
 
     if (file) {
       $('td.filetype', table).text(file.type);
       $('td.filesize', table).text(this.file_size(file.size));
       $('td.filemtime', table).text(file.mtime);
     }
   };
 
   // handle auth errors on folder list
   this.folder_list_auth_errors = function(result)
   {
     if (result && result.auth_errors) {
       if (!this.auth_errors)
         this.auth_errors = {};
 
       $.extend(this.auth_errors, result.auth_errors);
     }
 
     // ask for password to the first storage on the list
     $.each(this.auth_errors || [], function(i, v) {
       file_api.folder_list_auth_dialog(i, v);
       return false;
     });
   };
 
   // create dialog for user credentials of external storage
   this.folder_list_auth_dialog = function(label, driver)
   {
     var args = {width: 400, height: 300, buttons: {}},
       dialog = $('#files-folder-auth-dialog'),
       content = this.folder_list_auth_form(driver);
 
     dialog.find('table.propform').remove();
     $('.auth-options', dialog).before(content);
 
     args.buttons[this.t('kolab_files.save')] = function() {
       var data = {folder: label, list: 1};
 
       $('input', dialog).each(function() {
         data[this.name] = this.type == 'checkbox' && !this.checked ? '' : this.value;
       });
 
       file_api.open_dialog = this;
       file_api.req = file_api.set_busy(true, 'kolab_files.authenticating');
       file_api.request('folder_auth', data, 'folder_auth_response');
     };
 
     args.buttons[this.t('kolab_files.cancel')] = function() {
       delete file_api.auth_errors[label];
       kolab_dialog_close(this);
       // go to the next one
       file_api.folder_list_auth_errors();
     };
 
     args.title = this.t('kolab_files.folderauthtitle').replace('$title', label);
 
     // show dialog window
     kolab_dialog_show(dialog, args, function() {
       // focus first empty input
       $('input', dialog).each(function() {
         if (!this.value) {
           this.focus();
           return false;
         }
       });
     });
   };
 
   // folder_auth handler
   this.folder_auth_response = function(response)
   {
     if (!this.response(response))
       return;
 
-    var cnt = 0, folders,
+    var folders,
       folder = response.result.folder,
-      parent = $('#' + this.env.folders[folder].id);
+      id = 'rcmli' + rcmail.html_identifier_encode(folder),
+      parent = $('#' + id);
 
     // try parent window if the folder element does not exist
     if (!parent.length && window.parent && window.parent.rcmail) {
-      parent = $('#' + this.env.folders[folder].id, window.parent.document.body);
+      parent = $('#' + id, window.parent.document.body);
     }
 
     delete this.auth_errors[folder];
     kolab_dialog_close(this.open_dialog);
 
     // go to the next one
     this.folder_list_auth_errors();
 
-    // count folders on the list
-    $.each(this.env.folders, function() { cnt++; });
-
     // parse result
-    folders = this.folder_list_parse(response.result.list, cnt);
+    folders = this.folder_list_parse(response.result.list);
     delete folders[folder]; // remove root added in folder_list_parse()
 
     // add folders from the external source to the list
     $.each(folders, function(i, f) {
-      var row = file_api.folder_list_row(i, f);
-      parent.after(row);
-      parent = row;
+      file_api.folder_list_row(i, f, parent.get(0));
     });
 
     // add tree icons
-    this.folder_list_tree(folders);
+//    this.folder_list_tree(folders);
 
     $.extend(this.env.folders, folders);
   };
 
   // returns content of the external storage authentication form
   this.folder_list_auth_form = function(driver)
   {
     var rows = [];
 
     $.each(driver.form, function(fi, fv) {
       var id = 'authinput' + fi,
         attrs = {type: fi.match(/pass/) ? 'password' : 'text', size: 25, name: fi, id: id},
         input = $('<input>').attr(attrs);
 
       if (driver.form_values && driver.form_values[fi])
         input.attr({value: driver.form_values[fi]});
 
       rows.push($('<tr>')
         .append($('<td class="title">').append($('<label>').attr('for', id).text(fv)))
         .append($('<td>').append(input))
       );
     });
 
     return $('<table class="propform">').append(rows);
   };
 };
diff --git a/plugins/kolab_files/kolab_files.php b/plugins/kolab_files/kolab_files.php
index f598c4a0..9ff9a2a3 100644
--- a/plugins/kolab_files/kolab_files.php
+++ b/plugins/kolab_files/kolab_files.php
@@ -1,133 +1,134 @@
 <?php
 
 /**
  * Kolab files storage
  *
  * @version @package_version@
  * @author Aleksander Machniak <machniak@kolabsys.com>
  *
  * Copyright (C) 2013, 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/>.
  */
 
 class kolab_files extends rcube_plugin
 {
     // all task excluding 'login' and 'logout'
     public $task = '?(?!login|logout).*';
 
+    public $allowed_prefs = array('kolab_files_collapsed_folders');
     public $rc;
     public $home;
     private $engine;
 
     public function init()
     {
         $this->rc = rcube::get_instance();
 
         // Register hooks
         $this->add_hook('refresh', array($this, 'refresh'));
 
         // Plugin actions for other tasks
         $this->register_action('plugin.kolab_files', array($this, 'actions'));
 
         // Register task
         $this->register_task('files');
 
         // Register plugin task actions
         $this->register_action('index', array($this, 'actions'));
         $this->register_action('prefs', array($this, 'actions'));
         $this->register_action('open',  array($this, 'actions'));
 
         // we use libkolab::http_request() from libkolab with its configuration
         $this->require_plugin('libkolab');
 
         // Load UI from startup hook
         $this->add_hook('startup', array($this, 'startup'));
     }
 
     /**
      * Creates kolab_files_engine instance
      */
     private function engine()
     {
         if ($this->engine === null) {
             // the files module can be enabled/disabled by the kolab_auth plugin
             if ($this->rc->config->get('kolab_files_disabled') || !$this->rc->config->get('kolab_files_enabled', true)) {
                 return $this->engine = false;
             }
 
             $this->load_config();
 
             $url = $this->rc->config->get('kolab_files_url');
 
             if (!$url) {
                 return $this->engine = false;
             }
 
             require_once $this->home . DIRECTORY_SEPARATOR . 'lib' . DIRECTORY_SEPARATOR . 'kolab_files_engine.php';
 
             $this->engine = new kolab_files_engine($this, $url);
         }
 
         return $this->engine;
     }
 
     /**
      * Startup hook handler, initializes/enables Files UI
      */
     public function startup($args)
     {
         // call this from startup to give a chance to set
         // kolab_files_enabled/disabled in kolab_auth plugin
         $this->ui();
     }
 
     /**
      * Adds elements of files API user interface
      */
     private function ui()
     {
         if ($this->rc->output->type != 'html') {
             return;
         }
 
         if ($engine = $this->engine()) {
             $engine->ui();
         }
     }
 
     /**
      * Refresh hook handler
      */
     public function refresh($args)
     {
         // Here we are refreshing API session, so when we need it
         // the session will be active
         if ($engine = $this->engine()) {
             $this->rc->output->set_env('files_token', $engine->get_api_token());
         }
 
         return $args;
     }
 
     /**
      * Engine actions handler
      */
     public function actions()
     {
         if ($engine = $this->engine()) {
             $engine->actions();
         }
     }
 }
diff --git a/plugins/kolab_files/lib/kolab_files_engine.php b/plugins/kolab_files/lib/kolab_files_engine.php
index 75011954..2386cf10 100644
--- a/plugins/kolab_files/lib/kolab_files_engine.php
+++ b/plugins/kolab_files/lib/kolab_files_engine.php
@@ -1,1186 +1,1190 @@
 <?php
 
 /**
  * Kolab files storage engine
  *
  * @version @package_version@
  * @author Aleksander Machniak <machniak@kolabsys.com>
  *
  * Copyright (C) 2013, 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/>.
  */
 
 class kolab_files_engine
 {
     private $plugin;
     private $rc;
     private $timeout = 600;
     private $sort_cols = array('name', 'mtime', 'size');
 
     const API_VERSION = 2;
 
 
     /**
      * Class constructor
      */
     public function __construct($plugin, $url)
     {
         $this->url     = rcube_utils::resolve_url($url);
         $this->plugin  = $plugin;
         $this->rc      = $plugin->rc;
         $this->timeout = $this->rc->config->get('session_lifetime') * 60;
     }
 
     /**
      * User interface initialization
      */
     public function ui()
     {
         $this->plugin->add_texts('localization/');
 
         // set templates of Files UI and widgets
         if ($this->rc->task == 'mail') {
             if ($this->rc->action == 'compose') {
                 $template = 'compose_plugin';
             }
             else if (in_array($this->rc->action, array('show', 'preview', 'get'))) {
                 $template = 'message_plugin';
 
                 if ($this->rc->action == 'get') {
                     // add "Save as" button into attachment toolbar
                     $this->plugin->add_button(array(
                         'id'         => 'saveas',
                         'name'       => 'saveas',
                         'type'       => 'link',
                         'onclick'    => 'kolab_directory_selector_dialog()',
                         'class'      => 'button buttonPas saveas',
                         'classact'   => 'button saveas',
                         'label'      => 'kolab_files.save',
                         'title'      => 'kolab_files.saveto',
                         ), 'toolbar');
                 }
                 else {
                     // add "Save as" button into attachment menu
                     $this->plugin->add_button(array(
                         'id'         => 'attachmenusaveas',
                         'name'       => 'attachmenusaveas',
                         'type'       => 'link',
                         'wrapper'    => 'li',
                         'onclick'    => 'return false',
                         'class'      => 'icon active saveas',
                         'classact'   => 'icon active saveas',
                         'innerclass' => 'icon active saveas',
                         'label'      => 'kolab_files.saveto',
                         ), 'attachmentmenu');
                 }
             }
 
             $this->plugin->add_label('save', 'cancel', 'saveto',
                 'saveall', 'fromcloud', 'attachsel', 'selectfiles', 'attaching',
                 'collection_audio', 'collection_video', 'collection_image', 'collection_document',
                 'folderauthtitle', 'authenticating'
             );
         }
         else if ($this->rc->task == 'files') {
             $template = 'files';
 
             // get list of external sources
             $this->get_external_storage_drivers();
         }
 
         // add taskbar button
         if (empty($_REQUEST['framed'])) {
             $this->plugin->add_button(array(
                 'command'    => 'files',
                 'class'      => 'button-files',
                 'classsel'   => 'button-files button-selected',
                 'innerclass' => 'button-inner',
                 'label'      => 'kolab_files.files',
                 ), 'taskbar');
         }
 
         $this->plugin->include_stylesheet($this->plugin->local_skin_path().'/style.css');
 
         if (!empty($template)) {
+            $collapsed_folders = (string) $this->rc->config->get('kolab_files_collapsed_folders');
+
             $this->plugin->include_script($this->url . '/js/files_api.js');
             $this->plugin->include_script('kolab_files.js');
+            $this->rc->output->include_script('treelist.js');
             $this->rc->output->set_env('files_url', $this->url . '/api/');
             $this->rc->output->set_env('files_token', $this->get_api_token());
+            $this->rc->output->set_env('kolab_files_collapsed_folders', $collapsed_folders);
 
             // register template objects for dialogs (and main interface)
             $this->rc->output->add_handlers(array(
                 'folder-create-form' => array($this, 'folder_create_form'),
                 'folder-edit-form'   => array($this, 'folder_edit_form'),
                 'folder-mount-form'  => array($this, 'folder_mount_form'),
                 'folder-auth-options'=> array($this, 'folder_auth_options'),
                 'file-search-form'   => array($this, 'file_search_form'),
                 'file-edit-form'     => array($this, 'file_edit_form'),
                 'filelist'           => array($this, 'file_list'),
                 'filequotadisplay'   => array($this, 'quota_display'),
             ));
 
             if ($this->rc->task != 'files') {
                 // add dialog content at the end of page body
                 $this->rc->output->add_footer(
                     $this->rc->output->parse('kolab_files.' . $template, false, false));
             }
         }
     }
 
     /**
      * Engine actions handler
      */
     public function actions()
     {
         if ($this->rc->task == 'files' && $this->rc->action) {
             $action = $this->rc->action;
         }
         else if ($this->rc->task != 'files' && $_POST['act']) {
             $action = $_POST['act'];
         }
         else {
             $action = 'index';
         }
 
         $method = 'action_' . str_replace('-', '_', $action);
 
         if (method_exists($this, $method)) {
             $this->plugin->add_texts('localization/');
             $this->{$method}();
         }
     }
 
     /**
      * Template object for folder creation form
      */
     public function folder_create_form($attrib)
     {
         $attrib['name'] = 'folder-create-form';
         if (empty($attrib['id'])) {
             $attrib['id'] = 'folder-create-form';
         }
 
         $input_name    = new html_inputfield(array('id' => 'folder-name', 'name' => 'name', 'size' => 30));
         $select_parent = new html_select(array('id' => 'folder-parent', 'name' => 'parent'));
         $table         = new html_table(array('cols' => 2, 'class' => 'propform'));
 
         $table->add('title', html::label('folder-name', rcube::Q($this->plugin->gettext('foldername'))));
         $table->add(null, $input_name->show());
         $table->add('title', html::label('folder-parent', rcube::Q($this->plugin->gettext('folderinside'))));
         $table->add(null, $select_parent->show());
 
         $out = $table->show();
 
         // add form tag around text field
         if (empty($attrib['form'])) {
             $out = $this->rc->output->form_tag($attrib, $out);
         }
 
         $this->plugin->add_label('foldercreating', 'foldercreatenotice', 'create', 'foldercreate', 'cancel');
         $this->rc->output->add_gui_object('folder-create-form', $attrib['id']);
 
         return $out;
     }
 
     /**
      * Template object for folder editing form
      */
     public function folder_edit_form($attrib)
     {
         $attrib['name'] = 'folder-edit-form';
         if (empty($attrib['id'])) {
             $attrib['id'] = 'folder-edit-form';
         }
 
         $input_name    = new html_inputfield(array('id' => 'folder-edit-name', 'name' => 'name', 'size' => 30));
         $select_parent = new html_select(array('id' => 'folder-edit-parent', 'name' => 'parent'));
         $table         = new html_table(array('cols' => 2, 'class' => 'propform'));
 
         $table->add('title', html::label('folder-name', rcube::Q($this->plugin->gettext('foldername'))));
         $table->add(null, $input_name->show());
         $table->add('title', html::label('folder-parent', rcube::Q($this->plugin->gettext('folderinside'))));
         $table->add(null, $select_parent->show());
 
         $out = $table->show();
 
         // add form tag around text field
         if (empty($attrib['form'])) {
             $out = $this->rc->output->form_tag($attrib, $out);
         }
 
         $this->plugin->add_label('folderupdating', 'folderupdatenotice', 'save', 'folderedit', 'cancel');
         $this->rc->output->add_gui_object('folder-edit-form', $attrib['id']);
 
         return $out;
     }
 
     /**
      * Template object for folder mounting form
      */
     public function folder_mount_form($attrib)
     {
         $sources = $this->rc->output->get_env('external_sources');
 
         if (empty($sources) || !is_array($sources)) {
             return '';
         }
 
         $attrib['name'] = 'folder-mount-form';
         if (empty($attrib['id'])) {
             $attrib['id'] = 'folder-mount-form';
         }
 
         // build form content
         $table        = new html_table(array('cols' => 2, 'class' => 'propform'));
         $input_name   = new html_inputfield(array('id' => 'folder-mount-name', 'name' => 'name', 'size' => 30));
         $input_driver = new html_radiobutton(array('name' => 'driver', 'size' => 30));
 
         $table->add('title', html::label('folder-mount-name', rcube::Q($this->plugin->gettext('name'))));
         $table->add(null, $input_name->show());
 
         foreach ($sources as $key => $source) {
             $id    = 'source-' . $key;
             $form  = new html_table(array('cols' => 2, 'class' => 'propform driverform'));
 
             foreach ((array) $source['form'] as $idx => $label) {
                 $iid = $id . '-' . $idx;
                 $type  = stripos($idx, 'pass') !== false ? 'html_passwordfield' : 'html_inputfield';
                 $input = new $type(array('size' => 30));
 
                 $form->add('title', html::label($iid, rcube::Q($label)));
                 $form->add(null, $input->show('', array(
                         'id'   => $iid,
                         'name' => $key . '[' . $idx . ']'
                 )));
             }
 
             $row = $input_driver->show(null, array('value' => $key))
                 . html::img(array('src' => $source['image'], 'alt' => $key, 'title' => $source['name']))
                 . html::div(null, html::span('name', rcube::Q($source['name']))
                     . html::br()
                     . html::span('description', rcube::Q($source['description']))
                     . $form->show()
                 );
 
             $table->add(array('id' => $id, 'colspan' => 2, 'class' => 'source'), $row);
         }
 
         $out = $table->show() . $this->folder_auth_options(array('suffix' => '-form'));
 
         // add form tag around text field
         if (empty($attrib['form'])) {
             $out = $this->rc->output->form_tag($attrib, $out);
         }
 
         $this->plugin->add_label('foldermounting', 'foldermountnotice', 'foldermount',
             'save', 'cancel', 'folderauthtitle', 'authenticating'
         );
         $this->rc->output->add_gui_object('folder-mount-form', $attrib['id']);
 
         return $out;
     }
 
     /**
      * Template object for folder authentication options
      */
     public function folder_auth_options($attrib)
     {
         $checkbox = new html_checkbox(array(
             'name'  => 'store_passwords',
             'value' => '1',
             'id'    => 'auth-pass-checkbox' . $attrib['suffix'],
         ));
 
         return html::div('auth-options', $checkbox->show(). '&nbsp;'
             . html::label('auth-pass-checkbox' . $attrib['suffix'], $this->plugin->gettext('storepasswords'))
             . html::span('description', $this->plugin->gettext('storepasswordsdesc'))
         );
     }
 
     /**
      * Template object for file_edit form
      */
     public function file_edit_form($attrib)
     {
         $attrib['name'] = 'file-edit-form';
         if (empty($attrib['id'])) {
             $attrib['id'] = 'file-edit-form';
         }
 
         $input_name = new html_inputfield(array('id' => 'file-name', 'name' => 'name', 'size' => 30));
         $table      = new html_table(array('cols' => 2, 'class' => 'propform'));
 
         $table->add('title', html::label('file-name', rcube::Q($this->plugin->gettext('filename'))));
         $table->add(null, $input_name->show());
 
         $out = $table->show();
 
         // add form tag around text field
         if (empty($attrib['form'])) {
             $out = $this->rc->output->form_tag($attrib, $out);
         }
 
         $this->plugin->add_label('save', 'cancel', 'fileupdating', 'fileedit');
         $this->rc->output->add_gui_object('file-edit-form', $attrib['id']);
 
         return $out;
     }
 
     /**
      * Template object for file search form in "From cloud" dialog
      */
     public function file_search_form($attrib)
     {
         $attrib['name'] = '_q';
 
         if (empty($attrib['id'])) {
             $attrib['id'] = 'filesearchbox';
         }
         if ($attrib['type'] == 'search' && !$this->rc->output->browser->khtml) {
             unset($attrib['type'], $attrib['results']);
         }
 
         $input_q = new html_inputfield($attrib);
         $out = $input_q->show();
 
         // add some labels to client
         $this->rc->output->add_label('searching');
         $this->rc->output->add_gui_object('filesearchbox', $attrib['id']);
 
         // add form tag around text field
         if (empty($attrib['form'])) {
             $out = $this->rc->output->form_tag(array(
                     'action'   => '?_task=files',
                     'name'     => "filesearchform",
                     'onsubmit' => rcmail_output::JS_OBJECT_NAME . ".command('files-search'); return false",
                 ), $out);
         }
 
         return $out;
     }
 
     /**
      * Template object for files list
      */
     public function file_list($attrib)
     {
         // define list of cols to be displayed based on parameter or config
         if (empty($attrib['columns'])) {
             $list_cols     = $this->rc->config->get('kolab_files_list_cols');
             $dont_override = $this->rc->config->get('dont_override');
             $a_show_cols = is_array($list_cols) ? $list_cols : array('name');
             $this->rc->output->set_env('col_movable', !in_array('kolab_files_list_cols', (array)$dont_override));
         }
         else {
             $columns     = str_replace(array("'", '"'), '', $attrib['columns']);
             $a_show_cols = preg_split('/[\s,;]+/', $columns);
         }
 
         // make sure 'name' and 'options' column is present
         if (!in_array('name', $a_show_cols)) {
             array_unshift($a_show_cols, 'name');
         }
         if (!in_array('options', $a_show_cols)) {
             array_unshift($a_show_cols, 'options');
         }
 
         $attrib['columns'] = $a_show_cols;
 
         // save some variables for use in ajax list
         $_SESSION['kolab_files_list_attrib'] = $attrib;
 
         // For list in dialog(s) remove all option-like columns
         if ($this->rc->task != 'files') {
             $a_show_cols = array_intersect($a_show_cols, $this->sort_cols);
         }
 
         // set default sort col/order to session
         if (!isset($_SESSION['kolab_files_sort_col']))
             $_SESSION['kolab_files_sort_col'] = $this->rc->config->get('kolab_files_sort_col') ?: 'name';
         if (!isset($_SESSION['kolab_files_sort_order']))
             $_SESSION['kolab_files_sort_order'] = strtoupper($this->rc->config->get('kolab_files_sort_order') ?: 'asc');
 
         // set client env
         $this->rc->output->add_gui_object('filelist', $attrib['id']);
         $this->rc->output->set_env('sort_col', $_SESSION['kolab_files_sort_col']);
         $this->rc->output->set_env('sort_order', $_SESSION['kolab_files_sort_order']);
         $this->rc->output->set_env('coltypes', $a_show_cols);
         $this->rc->output->set_env('search_threads', $this->rc->config->get('kolab_files_search_threads'));
 
         $this->rc->output->include_script('list.js');
 
         // attach css rules for mimetype icons
         $this->plugin->include_stylesheet($this->url . '/skins/default/images/mimetypes/style.css');
 
         $thead = '';
         foreach ($this->file_list_head($attrib, $a_show_cols) as $cell) {
             $thead .= html::tag('th', array('class' => $cell['className'], 'id' => $cell['id']), $cell['html']);
         }
 
         return html::tag('table', $attrib,
             html::tag('thead', null, html::tag('tr', null, $thead)) . html::tag('tbody', null, ''),
             array('style', 'class', 'id', 'cellpadding', 'cellspacing', 'border', 'summary'));
     }
 
     /**
      * Creates <THEAD> for message list table
      */
     protected function file_list_head($attrib, $a_show_cols)
     {
         $skin_path = $_SESSION['skin_path'];
 //        $image_tag = html::img(array('src' => "%s%s", 'alt' => "%s"));
 
         // check to see if we have some settings for sorting
         $sort_col   = $_SESSION['kolab_files_sort_col'];
         $sort_order = $_SESSION['kolab_files_sort_order'];
 
         $dont_override  = (array)$this->rc->config->get('dont_override');
         $disabled_sort  = in_array('message_sort_col', $dont_override);
         $disabled_order = in_array('message_sort_order', $dont_override);
 
         $this->rc->output->set_env('disabled_sort_col', $disabled_sort);
         $this->rc->output->set_env('disabled_sort_order', $disabled_order);
 
         // define sortable columns
         if ($disabled_sort)
             $a_sort_cols = $sort_col && !$disabled_order ? array($sort_col) : array();
         else
             $a_sort_cols = $this->sort_cols;
 
         if (!empty($attrib['optionsmenuicon'])) {
             $onclick = 'return ' . JS_OBJECT_NAME . ".command('menu-open', 'filelistmenu', this, event)";
             $inner   = $this->rc->gettext('listoptions');
 
             if (is_string($attrib['optionsmenuicon']) && $attrib['optionsmenuicon'] != 'true') {
                 $inner = html::img(array('src' => $skin_path . $attrib['optionsmenuicon'], 'alt' => $this->rc->gettext('listoptions')));
             }
 
             $list_menu = html::a(array(
                 'href'     => '#list-options',
                 'onclick'  => $onclick,
                 'class'    => 'listmenu',
                 'id'       => 'listmenulink',
                 'title'    => $this->rc->gettext('listoptions'),
                 'tabindex' => '0',
             ), $inner);
         }
         else {
             $list_menu = '';
         }
 
         $cells = array();
 
         foreach ($a_show_cols as $col) {
             // get column name
             switch ($col) {
 /*
             case 'status':
                 $col_name = '<span class="' . $col .'">&nbsp;</span>';
                 break;
 */
             case 'options':
                 $col_name = $list_menu;
                 break;
             default:
                 $col_name = rcube::Q($this->plugin->gettext($col));
             }
 
             // make sort links
             if (in_array($col, $a_sort_cols)) {
                 $col_name = html::a(array(
                         'href'    => "#sort",
                         'onclick' => 'return '.JS_OBJECT_NAME.".command('files-sort','".$col."',this)",
                         'title'   => $this->plugin->gettext('sortby')
                     ), $col_name);
             }
             else if ($col_name[0] != '<')
                 $col_name = '<span class="' . $col .'">' . $col_name . '</span>';
 
             $sort_class = $col == $sort_col && !$disabled_order ? " sorted$sort_order" : '';
             $class_name = $col.$sort_class;
 
             // put it all together
             $cells[] = array('className' => $class_name, 'id' => "rcm$col", 'html' => $col_name);
         }
 
         return $cells;
     }
 
     /**
      * Update files list object
      */
     protected function file_list_update($prefs)
     {
         $attrib = $_SESSION['kolab_files_list_attrib'];
 
         if (!empty($prefs['kolab_files_list_cols'])) {
             $attrib['columns'] = $prefs['kolab_files_list_cols'];
             $_SESSION['kolab_files_list_attrib'] = $attrib;
         }
 
         $a_show_cols = $attrib['columns'];
         $head        = '';
 
         foreach ($this->file_list_head($attrib, $a_show_cols) as $cell) {
             $head .= html::tag('td', array('class' => $cell['className'], 'id' => $cell['id']), $cell['html']);
         }
 
         $head = html::tag('tr', null, $head);
 
         $this->rc->output->set_env('coltypes', $a_show_cols);
         $this->rc->output->command('files_list_update', $head);
     }
 
     /**
      * Template object for file info box
      */
     public function file_info_box($attrib)
     {
         // print_r($this->file_data, true);
         $table = new html_table(array('cols' => 2, 'class' => $attrib['class']));
 
         // file name
         $table->add('label', $this->plugin->gettext('name').':');
         $table->add('data filename', $this->file_data['name']);
 
         // file type
         // @TODO: human-readable type name
         $table->add('label', $this->plugin->gettext('type').':');
         $table->add('data filetype', $this->file_data['type']);
 
         // file size
         $table->add('label', $this->plugin->gettext('size').':');
         $table->add('data filesize', $this->rc->show_bytes($this->file_data['size']));
 
         // file modification time
         $table->add('label', $this->plugin->gettext('mtime').':');
         $table->add('data filemtime', $this->file_data['mtime']);
 
         // @TODO: for images: width, height, color depth, etc.
         // @TODO: for text files: count of characters, lines, words
 
         return $table->show();
     }
 
     /**
      * Template object for file preview frame
      */
     public function file_preview_frame($attrib)
     {
         if (empty($attrib['id'])) {
             $attrib['id'] = 'filepreviewframe';
         }
 
         if ($frame = $this->file_data['viewer']['frame']) {
             return $frame;
         }
 
         if ($href = $this->file_data['viewer']['href']) {
             // file href attribute must be an absolute URL (Bug #2063)
             if (!empty($href)) {
                 if (!preg_match('|^https?://|', $href)) {
                     $href = $this->url . '/api/' . $href;
                 }
             }
         }
         else {
             $token = $this->get_api_token();
             $href  = $this->url . '/api/?method=file_get'
                 . '&file=' . urlencode($this->file_data['filename'])
                 . '&token=' . urlencode($token);
         }
 
         $this->rc->output->add_gui_object('preview_frame', $attrib['id']);
 
         $attrib['allowfullscreen'] = true;
         $attrib['src']             = $href;
         $attrib['onload']          = 'kolab_files_frame_load(this)';
 
         return html::iframe($attrib);
     }
 
     /**
      * Template object for quota display
      */
     public function quota_display($attrib)
     {
         if (!$attrib['id']) {
             $attrib['id'] = 'rcmquotadisplay';
         }
 
         $quota_type = !empty($attrib['display']) ? $attrib['display'] : 'text';
 
         $this->rc->output->add_gui_object('quotadisplay', $attrib['id']);
         $this->rc->output->set_env('quota_type', $quota_type);
 
         // get quota
         $token   = $this->get_api_token();
         $request = $this->get_request(array('method' => 'quota'), $token);
 
         // send request to the API
         try {
             $response = $request->send();
             $status   = $response->getStatus();
             $body     = @json_decode($response->getBody(), true);
 
             if ($status == 200 && $body['status'] == 'OK') {
                 $quota = $body['result'];
             }
             else {
                 throw new Exception($body['reason']);
             }
         }
         catch (Exception $e) {
             rcube::raise_error($e, true, false);
             $quota = array('total' => 0, 'percent' => 0);
         }
 
         $quota = rcube_output::json_serialize($quota);
 
         $this->rc->output->add_script(rcmail_output::JS_OBJECT_NAME . ".files_set_quota($quota);", 'docready');
 
         return html::span($attrib, '');
     }
 
     /**
      * Get API token for current user session, authenticate if needed
      */
     public function get_api_token()
     {
         $token = $_SESSION['kolab_files_token'];
         $time  = $_SESSION['kolab_files_time'];
 
         if ($token && time() - $this->timeout < $time) {
             if (time() - $time <= $this->timeout / 2) {
                 return $token;
             }
         }
 
         $request = $this->get_request(array('method' => 'ping'), $token);
 
         try {
             $url = $request->getUrl();
 
             // Send ping request
             if ($token) {
                 $url->setQueryVariables(array('method' => 'ping'));
                 $request->setUrl($url);
                 $response = $request->send();
                 $status   = $response->getStatus();
 
                 if ($status == 200 && ($body = json_decode($response->getBody(), true))) {
                     if ($body['status'] == 'OK') {
                         $_SESSION['kolab_files_time']  = time();
                         return $token;
                     }
                 }
             }
 
             // Go with authenticate request
             $url->setQueryVariables(array('method' => 'authenticate', 'version' => self::API_VERSION));
             $request->setUrl($url);
             $request->setAuth($this->rc->user->get_username(), $this->rc->decrypt($_SESSION['password']));
             $response = $request->send();
             $status   = $response->getStatus();
 
             if ($status == 200 && ($body = json_decode($response->getBody(), true))) {
                 $token = $body['result']['token'];
 
                 if ($token) {
                     $_SESSION['kolab_files_token'] = $token;
                     $_SESSION['kolab_files_time']  = time();
                     $_SESSION['kolab_files_caps']  = $body['result']['capabilities'];
                 }
             }
             else {
                 throw new Exception(sprintf("Authenticate error (Status: %d)", $status));
             }
         }
         catch (Exception $e) {
             rcube::raise_error($e, true, false);
         }
 
         return $token;
     }
 
     /**
      * Initialize HTTP_Request object
      */
     protected function get_request($get = null, $token = null)
     {
         $url = $this->url . '/api/';
 
         if (!$this->request) {
             $config = array(
                 'store_body'       => true,
                 'follow_redirects' => true,
             );
 
             $this->request = libkolab::http_request($url, 'GET', $config);
         }
         else {
             // cleanup
             try {
                 $this->request->setBody('');
                 $this->request->setUrl($url);
                 $this->request->setMethod(HTTP_Request2::METHOD_GET);
             }
             catch (Exception $e) {
                 rcube::raise_error($e, true, true);
             }
         }
 
         if ($token) {
             $this->request->setHeader('X-Session-Token', $token);
         }
 
         if (!empty($get)) {
             $url = $this->request->getUrl();
             $url->setQueryVariables($get);
             $this->request->setUrl($url);
         }
 
         // some HTTP server configurations require this header
         $this->request->setHeader('accept', "application/json,text/javascript,*/*");
 
         return $this->request;
     }
 
     /**
      * Handler for main files interface (Files task)
      */
     protected function action_index()
     {
         $this->plugin->add_label(
             'folderdeleting', 'folderdeleteconfirm', 'folderdeletenotice',
             'uploading', 'attaching', 'uploadsizeerror',
             'filedeleting', 'filedeletenotice', 'filedeleteconfirm',
             'filemoving', 'filemovenotice', 'filemoveconfirm', 'filecopying', 'filecopynotice',
             'collection_audio', 'collection_video', 'collection_image', 'collection_document',
             'fileskip', 'fileskipall', 'fileoverwrite', 'fileoverwriteall'
         );
 
         $this->rc->output->add_label('uploadprogress', 'GB', 'MB', 'KB', 'B');
         $this->rc->output->set_pagetitle($this->plugin->gettext('files'));
         $this->rc->output->set_env('file_mimetypes', $this->get_mimetypes());
         $this->rc->output->set_env('files_quota', $_SESSION['kolab_files_caps']['QUOTA']);
         $this->rc->output->set_env('files_max_upload', $_SESSION['kolab_files_caps']['MAX_UPLOAD']);
         $this->rc->output->set_env('files_progress_name', $_SESSION['kolab_files_caps']['PROGRESS_NAME']);
         $this->rc->output->set_env('files_progress_time', $_SESSION['kolab_files_caps']['PROGRESS_TIME']);
         $this->rc->output->send('kolab_files.files');
     }
 
     /**
      * Handler for preferences save action
      */
     protected function action_prefs()
     {
         $dont_override = (array)$this->rc->config->get('dont_override');
         $prefs = array();
         $opts  = array(
             'kolab_files_sort_col' => true,
             'kolab_files_sort_order' => true,
             'kolab_files_list_cols' => false,
         );
 
         foreach ($opts as $o => $sess) {
             if (isset($_POST[$o]) && !in_array($o, $dont_override)) {
                 $prefs[$o] = rcube_utils::get_input_value($o, rcube_utils::INPUT_POST);
                 if ($sess) {
                     $_SESSION[$o] = $prefs[$o];
                 }
 
                 if ($o == 'kolab_files_list_cols') {
                     $update_list = true;
                 }
             }
         }
 
         // save preference values
         if (!empty($prefs)) {
             $this->rc->user->save_prefs($prefs);
         }
 
         if (!empty($update_list)) {
             $this->file_list_update($prefs);
         }
 
         $this->rc->output->send();
     }
 
     /**
      * Handler for file open action
      */
     protected function action_open()
     {
         $file = rcube_utils::get_input_value('file', rcube_utils::INPUT_GET);
 
         // get file info
         $token   = $this->get_api_token();
         $request = $this->get_request(array(
             'method' => 'file_info',
             'file'   => $file,
             'viewer' => !empty($_GET['viewer']),
             ), $token);
 
         // send request to the API
         try {
             $response = $request->send();
             $status   = $response->getStatus();
             $body     = @json_decode($response->getBody(), true);
 
             if ($status == 200 && $body['status'] == 'OK') {
                 $this->file_data = $body['result'];
             }
             else {
                 throw new Exception($body['reason']);
             }
         }
         catch (Exception $e) {
             rcube::raise_error(array(
                 'code' => 500, 'type' => 'php', 'line' => __LINE__, 'file' => __FILE__,
                 'message' => $e->getMessage()),
                 true, true);
         }
 
         $this->file_data['filename'] = $file;
 
         $this->plugin->add_label('filedeleteconfirm', 'filedeleting', 'filedeletenotice');
 
         // register template objects for dialogs (and main interface)
         $this->rc->output->add_handlers(array(
             'fileinfobox'      => array($this, 'file_info_box'),
             'filepreviewframe' => array($this, 'file_preview_frame'),
         ));
 
         // this one is for styling purpose
         $this->rc->output->set_env('extwin', true);
         $this->rc->output->set_env('file', $file);
         $this->rc->output->set_env('file_data', $this->file_data);
         $this->rc->output->set_pagetitle(rcube::Q($file));
         $this->rc->output->send('kolab_files.filepreview');
     }
 
     /**
      * Handler for "save all attachments into cloud" action
      */
     protected function action_save_file()
     {
 //        $source = rcube_utils::get_input_value('source', rcube_utils::INPUT_POST);
         $uid    = rcube_utils::get_input_value('uid', rcube_utils::INPUT_POST);
         $dest   = rcube_utils::get_input_value('dest', rcube_utils::INPUT_POST);
         $id     = rcube_utils::get_input_value('id', rcube_utils::INPUT_POST);
         $name   = rcube_utils::get_input_value('name', rcube_utils::INPUT_POST);
 
         $temp_dir = unslashify($this->rc->config->get('temp_dir'));
         $message  = new rcube_message($uid);
         $request  = $this->get_request();
         $url      = $request->getUrl();
         $files    = array();
         $errors   = array();
         $attachments = array();
 
         $request->setMethod(HTTP_Request2::METHOD_POST);
         $request->setHeader('X-Session-Token', $this->get_api_token());
         $url->setQueryVariables(array('method' => 'file_upload', 'folder' => $dest));
         $request->setUrl($url);
 
         foreach ($message->attachments as $attach_prop) {
             if (empty($id) || $id == $attach_prop->mime_id) {
                 $filename = strlen($name) ? $name : rcmail_attachment_name($attach_prop, true);
                 $attachments[$filename] = $attach_prop;
             }
         }
 
         // @TODO: handle error
         // @TODO: implement file upload using file URI instead of body upload
 
         foreach ($attachments as $attach_name => $attach_prop) {
             $path = tempnam($temp_dir, 'rcmAttmnt');
 
             // save attachment to file
             if ($fp = fopen($path, 'w+')) {
                 $message->get_part_body($attach_prop->mime_id, false, 0, $fp);
             }
             else {
                 $errors[] = true;
                 rcube::raise_error(array(
                     'code' => 500, 'type' => 'php', 'line' => __LINE__, 'file' => __FILE__,
                     'message' => "Unable to save attachment into file $path"),
                     true, false);
                 continue;
             }
 
             fclose($fp);
 
             // send request to the API
             try {
                 $request->setBody('');
                 $request->addUpload('file[]', $path, $attach_name, $attach_prop->mimetype);
                 $response = $request->send();
                 $status   = $response->getStatus();
                 $body     = @json_decode($response->getBody(), true);
 
                 if ($status == 200 && $body['status'] == 'OK') {
                     $files[] = $attach_name;
                 }
                 else {
                     throw new Exception($body['reason']);
                 }
             }
             catch (Exception $e) {
                 unlink($path);
                 $errors[] = $e->getMessage();
                 rcube::raise_error(array(
                     'code' => 500, 'type' => 'php', 'line' => __LINE__, 'file' => __FILE__,
                     'message' => $e->getMessage()),
                     true, false);
                 continue;
             }
 
             // clean up
             unlink($path);
             $request->setBody('');
         }
 
         if ($count = count($files)) {
             $msg = $this->plugin->gettext(array('name' => 'saveallnotice', 'vars' => array('n' => $count)));
             $this->rc->output->show_message($msg, 'confirmation');
         }
         if ($count = count($errors)) {
             $msg = $this->plugin->gettext(array('name' => 'saveallerror', 'vars' => array('n' => $count)));
             $this->rc->output->show_message($msg, 'error');
         }
 
         // @TODO: update quota indicator, make this optional in case files aren't stored in IMAP
 
         $this->rc->output->send();
     }
 
     /**
      * Handler for "add attachments from the cloud" action
      */
     protected function action_attach_file()
     {
         $files      = rcube_utils::get_input_value('files', rcube_utils::INPUT_POST);
         $uploadid   = rcube_utils::get_input_value('uploadid', rcube_utils::INPUT_POST);
         $COMPOSE_ID = rcube_utils::get_input_value('id', rcube_utils::INPUT_POST);
         $COMPOSE    = null;
         $errors     = array();
 
         if ($COMPOSE_ID && $_SESSION['compose_data_'.$COMPOSE_ID]) {
             $COMPOSE =& $_SESSION['compose_data_'.$COMPOSE_ID];
         }
 
         if (!$COMPOSE) {
             die("Invalid session var!");
         }
 
         // attachment upload action
         if (!is_array($COMPOSE['attachments'])) {
             $COMPOSE['attachments'] = array();
         }
 
         // clear all stored output properties (like scripts and env vars)
         $this->rc->output->reset();
 
         $temp_dir = unslashify($this->rc->config->get('temp_dir'));
         $request  = $this->get_request();
         $url      = $request->getUrl();
 
         // Use observer object to store HTTP response into a file
         require_once $this->plugin->home . DIRECTORY_SEPARATOR . 'lib' . DIRECTORY_SEPARATOR . 'kolab_files_observer.php';
         $observer = new kolab_files_observer();
 
         $request->setHeader('X-Session-Token', $this->get_api_token());
 
         // download files from the API and attach them
         foreach ($files as $file) {
             // decode filename
             $file = urldecode($file);
 
             // get file information
             try {
                 $url->setQueryVariables(array('method' => 'file_info', 'file' => $file));
                 $request->setUrl($url);
                 $response = $request->send();
                 $status   = $response->getStatus();
                 $body     = @json_decode($response->getBody(), true);
 
                 if ($status == 200 && $body['status'] == 'OK') {
                     $file_params = $body['result'];
                 }
                 else {
                     throw new Exception($body['reason']);
                 }
             }
             catch (Exception $e) {
                 $errors[] = $e->getMessage();
                 rcube::raise_error(array(
                     'code' => 500, 'type' => 'php', 'line' => __LINE__, 'file' => __FILE__,
                     'message' => $e->getMessage()),
                     true, false);
                 continue;
             }
 
             // set location of downloaded file
             $path = tempnam($temp_dir, 'rcmAttmnt');
             $observer->set_file($path);
 
             // download file
             try {
                 $url->setQueryVariables(array('method' => 'file_get', 'file' => $file));
                 $request->setUrl($url);
                 $request->attach($observer);
                 $response = $request->send();
                 $status   = $response->getStatus();
                 $response->getBody(); // returns nothing
                 $request->detach($observer);
 
                 if ($status != 200 || !file_exists($path)) {
                     throw new Exception("Unable to save file");
                 }
             }
             catch (Exception $e) {
                 $errors[] = $e->getMessage();
                 rcube::raise_error(array(
                     'code' => 500, 'type' => 'php', 'line' => __LINE__, 'file' => __FILE__,
                     'message' => $e->getMessage()),
                     true, false);
                 continue;
             }
 
             $attachment = array(
                 'path' => $path,
                 'size' => $file_params['size'],
                 'name' => $file_params['name'],
                 'mimetype' => $file_params['type'],
                 'group' => $COMPOSE_ID,
             );
 
             $attachment = $this->rc->plugins->exec_hook('attachment_save', $attachment);
 
             if ($attachment['status'] && !$attachment['abort']) {
                 $id = $attachment['id'];
 
                 // store new attachment in session
                 unset($attachment['data'], $attachment['status'], $attachment['abort']);
                 $COMPOSE['attachments'][$id] = $attachment;
 
                 if (($icon = $COMPOSE['deleteicon']) && is_file($icon)) {
                     $button = html::img(array(
                         'src' => $icon,
                         'alt' => $this->rc->gettext('delete')
                     ));
                 }
                 else {
                     $button = rcube::Q($this->rc->gettext('delete'));
                 }
 
                 $content = html::a(array(
                     'href' => "#delete",
                     'onclick' => sprintf("return %s.command('remove-attachment','rcmfile%s', this)", JS_OBJECT_NAME, $id),
                     'title' => $this->rc->gettext('delete'),
                     'class' => 'delete',
                 ), $button);
 
                 $content .= rcube::Q($attachment['name']);
 
                 $this->rc->output->command('add2attachment_list', "rcmfile$id", array(
                     'html'      => $content,
                     'name'      => $attachment['name'],
                     'mimetype'  => $attachment['mimetype'],
                     'classname' => rcmail_filetype2classname($attachment['mimetype'], $attachment['name']),
                     'complete'  => true), $uploadid);
             }
             else if ($attachment['error']) {
                 $errors[] = $attachment['error'];
             }
             else {
                 $errors[] = $this->plugin->gettext('attacherror');
             }
         }
 
         if (!empty($errors)) {
             $this->rc->output->command('display_message', $this->plugin->gettext('attacherror'), 'error');
             $this->rc->output->command('remove_from_attachment_list', $uploadid);
         }
 
         // send html page with JS calls as response
         $this->rc->output->command('auto_save_start', false);
         $this->rc->output->send();
     }
 
     /**
      * Returns mimetypes supported by File API viewers
      */
     protected function get_mimetypes()
     {
         $token   = $this->get_api_token();
         $request = $this->get_request(array('method' => 'mimetypes'), $token);
 
         // send request to the API
         try {
             $response = $request->send();
             $status   = $response->getStatus();
             $body     = @json_decode($response->getBody(), true);
 
             if ($status == 200 && $body['status'] == 'OK') {
                 $mimetypes = $body['result'];
             }
             else {
                 throw new Exception($body['reason']);
             }
         }
         catch (Exception $e) {
             rcube::raise_error(array(
                 'code' => 500, 'type' => 'php', 'line' => __LINE__, 'file' => __FILE__,
                 'message' => $e->getMessage()),
                 true, false);
         }
 
         return $mimetypes;
     }
 
     /**
      * Get list of available external storage drivers
      */
     protected function get_external_storage_drivers()
     {
         // first get configured sources from Chwala
         $token   = $this->get_api_token();
         $request = $this->get_request(array('method' => 'folder_types'), $token);
 
         // send request to the API
         try {
             $response = $request->send();
             $status   = $response->getStatus();
             $body     = @json_decode($response->getBody(), true);
 
             if ($status == 200 && $body['status'] == 'OK') {
                 $sources = $body['result'];
             }
             else {
                 throw new Exception($body['reason']);
             }
         }
         catch (Exception $e) {
             rcube::raise_error($e, true, false);
             return;
         }
 
         $this->rc->output->set_env('external_sources', $sources);
     }
 }