I use CyanogenMod 11 M12 (Android 4.4) on my own device, and I can’t confirm that the icon is too far on the left.
I think I won’t ever be able to make a a single GUI dialog that works on all Android versions. Maybe there’s an experienced Android developer somewhere who can help?
The first problem seems to be this one: Issue 2229: Calendar: Deleting one instance of a recurring event (excluding), results in duplication of it.. As it seems, the calendar provider doesn’t add an EXDATE when deleting a single occurence, but adds another event with STATUS: CANCELLED.
This behaviour is controlled by the calendar app/provider and not by DAVdroid. DAVdroid just gets two events from the calendar provider and so it syncs the two events.
Couldn’t reproduce the second problem. I did exactly as you said – EXDATE was set by MyKolab and then the event disappeared in the calendar as expected. I guess that’s because you’re using the default Android calender app while I use the pre-installed Samsung S Planner app. I think this problem is an instance of Issue 21426: Support for complete EXDATE format in recurring events in Calendar / pim.
Basically, this is an Android bug again. In this case, DAVdroid could provide a workaround by rewriting EXDATE to a format that the Android calendar provider understands. I have opened an enhancement issue for this, see #82
After a bit of tinkering, my device appeared also as a pointer as “Network Tablet Pen (0)” . Using it
xinput map-to-output “$( xinput list --id-only “Network Tablet Pen (0)” )” HDMI-0
worked like a charm