2006-12-27  Matthias Clasen  <mclasen@redhat.com>

        * gtk/gtkcellview.c (gtk_cell_view_set_model): Accept NULL.

        * gtk/gtkcombobox.c (gtk_combo_box_set_model):
        (gtk_combo_box_unset_model): Handle repeated unsetting
        of models without warnings.  (#367529, Robert Ancell)