Traceback (most recent call last):
  File "/usr/lib/python2.5/site-packages/bzrlib/plugins/gtk/revisionview.py", line 474, in _switch_page_cb
    self.signature_table.set_revision(self._revision)
  File "/usr/lib/python2.5/site-packages/bzrlib/plugins/gtk/revisionview.py", line 202, in set_revision
    revid = revision.revision_id
AttributeError: 'NoneType' object has no attribute 'revision_id'