Wrong behaviour of TreeModel when record is None
I find those issue when trying to use accessibility tools like Orca to read a treeview. It was only reading the first level because it needs to have the atk.Object.get_n_accessible_children [1] which uses the Model to loop over all the node of the tree.
The drawback is that now Orca fetch all the node of the treeview but only if present so it doesn't affect the normal users.
[1] http://pygtk.org/docs/pygtk/class-atkobject.html#method-atkobject--get-n-accessible-children