[Glade-users] gtk tree error

[srinivas]

hi;

      i want to display gtktreeview with expand, collapse functionality.
i created tree using glade, and later accessed that using
gtk_tree_view_set_model(), created tree view also. now when i want to
display using expand/collapse functionality, i am getting error like
this.
Gtk-CRITICAL **: file gtktreeitem.c: line 298
(gtk_tree_item_set_subtree): assertion `GTK_IS_TREE (subtree)' failed

what does it mean, am i supposed to create one more tree for subtree,
how to resolve the error;

thanks;

srinivas.