[horde] Kronolith/IMP "Accept and Update In My Calendar" Not Working

[Robert McAuley]

When clicking "Accept and update in my calendar" for a Kronolith event,
the event does not get added to my calendar.

Steps I'm doing to reproduce:

- Open shared calendar "Meeting Room" owned by user X
- Book meeting at any time, any day, inviting myself and 1 other user
(user Y), and send invite email
- Open invite email in IMP and click "accept and update my calendar"

My calendar is not updated when I do this.  I remember it was working
before I updated my Horde Groupware Email to 1.2.1, though I can't
confirm what version number it was when it last worked for me. (I
typically use Lightning, it was only today that a user alerted me to
this bug on IMP)

The Horde debug logs do not give much information - just debug info for
memcache servers/session handling, and alarms.  Nothing useful
pretaining to this bug.

Is there an option I am missing somewhere, maybe, or does this seem like
an actual bug?  My Default Calendar in Kronolith is set correctly - so
it's not that being a problem.

Any ideas?

- Rob