void gtk_menu_set_monitor ( GtkMenu* menu, gint monitor_num )
Informs GTK+ on which monitor a menu should be popped up. See gdk_monitor_get_geometry().
This function should be called from a
if the menu should not appear on the same monitor as the pointer.
This information can’t be reliably inferred from the coordinates
returned by a
GtkMenuPositionFunc, since, for very long menus,
these coordinates may extend beyond the monitor boundaries or even
the screen boundaries.