[kronolith] Delete events with Thunderbird/iCal does not work

[lst_hoe02 at kwsoft.de]

Hello

we are in progress to test migration Horde3 -> Horde4 and noticed some  
strange problem with new Kronolith used by Thunderbird11/Lightning as  
iCal network calendar. Creating and modify of events work fine, but  
deleted events does disapear and get sync back on next update. Test  
with same Thunderbird/Lighting settings against old Horde/Kronolith  
does not show this behaviour.

Any idea how to debug this

Regards

Andreas