Description of problem:
To reproduce :
Open the abrt applet
Enter some text in the "Search" input box.
Check and un-check the "All problems" checkbox.

Version-Release number of selected component:
gnome-abrt-0.2.10-1.fc18

Additional info:
cmdline:        python /usr/bin/gnome-abrt -p /var/tmp/abrt/ccpp-2013-04-28-23:35:32-7659
dso_list:       pygobject3-base-3.4.2-6.fc18.x86_64
executable:     /usr/bin/gnome-abrt
kernel:         3.8.6-203.fc18.x86_64
uid:            500
ureports_counter: 6

Truncated backtrace:
types.py:47:function:TypeError: Argument 1 does not allow None as a value

Traceback (most recent call last):
  File "/usr/lib64/python2.7/site-packages/gnome_abrt/views.py", line 453, in on_gac_opt_all_problems_activate
    conf['all_problems'] = self._builder.chb_all_problems.get_active()
  File "/usr/lib64/python2.7/site-packages/gnome_abrt/config.py", line 49, in __setitem__
    map(lambda o: o.option_updated(self, option), opt.observers)
  File "/usr/lib64/python2.7/site-packages/gnome_abrt/config.py", line 49, in <lambda>
    map(lambda o: o.option_updated(self, option), opt.observers)
  File "/usr/lib64/python2.7/site-packages/gnome_abrt/dbus_problems.py", line 65, in option_updated
    self.source.refresh()
  File "/usr/lib64/python2.7/site-packages/gnome_abrt/problems.py", line 307, in refresh
    self.notify()
  File "/usr/lib64/python2.7/site-packages/gnome_abrt/problems.py", line 61, in notify
    observer.changed(self, change_type, problem)
  File "/usr/lib64/python2.7/site-packages/gnome_abrt/problems.py", line 244, in changed
    self.parent.notify(change_type, problem)
  File "/usr/lib64/python2.7/site-packages/gnome_abrt/problems.py", line 271, in notify
    super(MultipleSources, self).notify(change_type, problem)
  File "/usr/lib64/python2.7/site-packages/gnome_abrt/problems.py", line 61, in notify
    observer.changed(self, change_type, problem)
  File "/usr/lib64/python2.7/site-packages/gnome_abrt/views.py", line 187, in changed
    self.wnd._reload_problems(source)
  File "/usr/lib64/python2.7/site-packages/gnome_abrt/views.py", line 288, in _reload_problems
    self._select_problem_iter(model.get_iter_first())
  File "/usr/lib64/python2.7/site-packages/gnome_abrt/views.py", line 308, in _select_problem_iter
    path = self._builder.tv_problems.get_model().get_path(pit)
  File "/usr/lib64/python2.7/site-packages/gi/types.py", line 47, in function
    return info.invoke(*args, **kwargs)
TypeError: Argument 1 does not allow None as a value

Local variables in innermost frame:
info: <gi.FunctionInfo object (get_path) at 0x0x1e699e0>
args: (<TreeModelFilter object at 0x239c690 (GtkTreeModelFilter at 0x24ce0d0)>, None)
kwargs: {}