Traceback (most recent call last):
  File "/usr/share/software-center/softwarecenter/app.py", line 496, in on_view_switcher_changed
    self.view_manager.set_active_view(view_id)
  File "/usr/share/software-center/softwarecenter/view/viewmanager.py", line 39, in set_active_view
    active_view_widget.init_view()
  File "/usr/share/software-center/softwarecenter/view/historypane.py", line 182, in init_view
    self.window.set_cursor(None)
AttributeError: 'NoneType' object has no attribute 'set_cursor'