Spurious critical warnings in console

[Michael Baranov <michael baranov gmail com>]

Hello!
I'm new to the list and new to gtkmm...

Here is a very simple standalone snippet that looks OK to me but 
produces warnings:

Gtk-CRITICAL **: gtk_list_store_get_path: assertion `iter->stamp == 
GTK_LIST_STORE (tree_model)->stamp' failed

In the snippet keys A/Z move selection up/down; Hit key Z several times 
to see the warnings.
Am I missing something?

Thanks for the help and a superb lib!

--
Michael Baranov