Traceback (most recent call last):
  File "/usr/share/alacarte/Alacarte/MainWindow.py", line 325, in on_new_separator_button_clicked
    self.editor.createSeparator(parent, after=after)
  File "/usr/share/alacarte/Alacarte/MenuEditor.py", line 250, in createSeparator
    self.__positionItem(parent, ('Separator',), before, after)
  File "/usr/share/alacarte/Alacarte/MenuEditor.py", line 694, in __positionItem
    current = parent.contents.index(item)
ValueError: ('Separator',) is not in list