abrt 1.1.1 detected a crash.

architecture: i686
cmdline: python /usr/lib/hamster-applet/hamster-applet --oaf-activate-iid=OAFIID:Hamster_Applet_Factory --oaf-ior-fd=25
component: hamster-applet
executable: /usr/lib/hamster-applet/hamster-applet
kernel: 2.6.32.16-150.fc12.i686.PAE
package: hamster-applet-2.28.3-0.1.20100215git.fc12
reason: applet.py:585:delete_selected:TypeError: iter should be a GtkTreeIter
release: Fedora release 12 (Constantine)

backtrace
-----
applet.py:585:delete_selected:TypeError: iter should be a GtkTreeIter

Traceback (most recent call last):
  File "/usr/lib/python2.6/site-packages/hamster/applet.py", line 713, in on_todays_keys
    self.delete_selected()
  File "/usr/lib/python2.6/site-packages/hamster/applet.py", line 585, in delete_selected
    next_row = model.iter_next(iter)
TypeError: iter should be a GtkTreeIter

Local variables in innermost frame:
model: <gtk.ListStore object at 0x8c6ffcc (GtkListStore at 0x8b2c5e0)>
selection: <gtk.TreeSelection object at 0x8c6fe8c (GtkTreeSelection at 0x8b37280)>
self: <hamster.applet.HamsterApplet object at 0x892cd6c>
iter: None

How to reproduce
-----
1.Insert activity
2.remove activity
3.