open invetation tab is empty. in merged view they are shown
Can you be more clear what you mean with tabbed view? I have no glue in what situation you are talking about a tabbed view - in korganizer/kmail/calednerview/...?
The tabbed view can be enabled in the settings -> views -> agenda view -> "Switch between views with tabs"
verified with our testinstance.
also valid for declinedinvitations.
Kolab support for KDE PIM is discontinued. Create a ticket on https://bugs.kde.org