Set the GtkAccelGroup which holds global accelerators for the menu.
This accelerator group needs to also be added to all windows that
this menu is being used in with gtk_window_add_accel_group(), in order
for those windows to support all the accelerators contained in this group.
Set the GtkAccelGroup which holds global accelerators for the menu. This accelerator group needs to also be added to all windows that this menu is being used in with gtk_window_add_accel_group(), in order for those windows to support all the accelerators contained in this group.