gtk_menu_set_tearoff_state()

[jos <j g a v riswick tue nl>]

HI!!!

I'd like to make a menu popup in the torn off state
upon a button press. To do this, in the button callback
function, I first pop up the menu, and then set the 
tearoff_state property to true:


gtk_menu_popup (GTK_MENU (widget), NULL, NULL, MenuPosition, 
                       event, bevent->button, bevent->time);
gtk_menu_set_title(GTK_MENU (widget),"Menu");
gtk_menu_set_tearoff_state(GTK_MENU(widget),TRUE);



however, when I do this, and run the program from the 
command line, I get two assertion failures:


Gtk-CRITICAL **: file gtkwidget.c: line 2971 (gtk_widget_reparent):
assertion `new_parent != NULL' failed.
Gtk-CRITICAL **: file gtkwidget.c: line 3786 (gtk_widget_set_usize):
assertion `widget != NULL' failed.



The menus to appear in the correct way however. 
When I don't tearoff the menus, I don't get the assertion
failures. What should I do to avoid the error messages?

Also I'd like to know how to get the sizes of the tearoff
menus including the window decorations, in order to do 
the right positioning.

best regards

jos