Comment 1 for bug 133139

The problem is in:
UpdateManager/UpdateManager.py:
def on_treeview_update_cursor_changed(self, widget):
...
id = button.connect("clicked",
                            lambda w,lock: lock.release(), lock)
        # wait for the dl-thread
        while lock.locked():
          time.sleep(0.05)
          while gtk.events_pending():
            gtk.main_iteration()
...

it looks like the main_iteration() can cause re-entrace of this function and that confuses the bottom bits.