[kronolith] timezone problem in Calendar Views

[Systeembeheer BCS]

We like the time of an event to appear in the different calendar views  
(Month, Week) so on the Calendar>User interface preference page we set  
"Choose the views to show event start and end times in:" to "Month,  
Week and Day Views". That works fine.

Now when creating a new event in the calendar, some users change the  
timezone in the event window from "Default" to "Europe/Amsterdam".  
That should not make a difference as Europe/Amsterdam is the default  
timezone anyway and all users are set to this. But it does make a  
difference:
- With the timezone of an event set to default, times displayed in the  
calendar views are correct.
- Events with the timezone set to Europe/Amsterdam appear with the  
start- en ending times displayed with an offset of -2 hours.

Running Horde Groupware 5.1.4, Kronolith version 4.1.5 on Ubuntu  
server 12.04LTS.
/etc/timezone on the system is set to Europe/Amsterdam, the 'date'  
command shows the correct local time from the command line.

Maybe related: although Ubuntu has the correct timezone setting, in  
Horde's "global prefs">"Locale and Time" setting all users have to set  
the default timezone to Europe/Amsterdam anyway to get the correct  
time in Horde. I assume Horde always references to UTC regardless of  
system settings?

Thanks...
Martin