treeview: seg fault When Collapsing a Row Containg a Selected Item

[Marshall Lake <mlake mlake net>]

I have a treeview/treestore containing many top-level rows.  Each 
top-level row contains many children.  The treeview works fine except for 
one thing.  If the user expands a top-level row, selects a child, and then 
collapses that row the program seg faults with the console error:
gtk_tree_store_get_value: assertion `iter->stamp == GTK_TREE_STORE (tree_model)->stamp' failed
gtype.c:3351: type id `0' is invalid
can't peek value table for type `<invalid>' which is not currently referenced

The treeview works fine if the user never collapses the row and goes on to 
make another selection, either in that same top-level or a different 
top-level.  Also, if a row is expanded and then collapsed with no child 
being selected it works fine.
As an aside (?), I tried gtk_tree_selection_unselect_iter() on the child 
after it was selected and got a seg fault and the same error as noted 
above at the point the gtk_tree_selection_unselect_iter() was executed.
Can someone tell me what might need to be done to avoid the seg fault?

--
Marshall Lake -- mlake mlake net -- http://mlake.net