Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/UpdateManager/UpdateManager.py", line 1096, in on_button_dist_upgrade_clicked
    fetcher.run()
  File "/usr/lib/python2.7/dist-packages/UpdateManager/Core/DistUpgradeFetcherCore.py", line 245, in run
    if not self.showReleaseNotes():
  File "/usr/lib/python2.7/dist-packages/UpdateManager/DistUpgradeFetcher.py", line 65, in showReleaseNotes
    return self._try_show_release_notes_textview()
  File "/usr/lib/python2.7/dist-packages/UpdateManager/DistUpgradeFetcher.py", line 88, in _try_show_release_notes_textview
    self.window_main.window.set_cursor(Gdk.Cursor.new(Gdk.CursorType.WATCH))
AttributeError: 'Window' object has no attribute 'window'