Please describe the problem:
Hitting 'save' after editing the start time of an activity record deletes the record

Steps to reproduce:
1. Start tracking an activity
2. click the applet and select the little "pencil writing on paper" icon on the right of the current activity to pop up the 'update activity' dialog
3. Edit the start time for the activity
4. Press 'save'


Actual results:
The current activity record is deleted and the applet reverts to "no activity"

Expected results:
The current activity should continue to exist, but with the changed start time

Does this happen every time?
Yes.  The edited activity is also deleted when you edit an existing (not the current) activity record.

Other information:
Running Ubuntu 8.10 AMD64, using the packaged version of hamster applet.