The intended behavior is to update whenever
- dbus signaled a change in the calendar
- the day changed
- for one of the displayed events the end time passed by.

I added "Update when switch to the desktop" option for
those users who use programs which changes the
calendardb directly (no dbus signals are emitted -
erminig for example).

It may be that I broke the automatic update. I made quite huge
changes and must admit I didn't test the automatic update.

Thank you for reporting this.

Nicolai