After removing a vertex with remove_vertex, properties are not updated.
further using _remove_vertex properties does the job.
Probably due to wrong call in tree.py (remove vertex does not return vid), line 535,536:
vid = super(PropertyTree, self).remove_vertex(vid, reparent_child=reparent_child) self._remove_vertex_properties(vid)
guessing that :
super(PropertyTree, self).remove_vertex(vid, reparent_child=reparent_child) self._remove_vertex_properties(vid)
should be okay