Sorry because I Know this is not GMF specific subject, but perhaps
someone of you has done this: I need to customize / override the default
main menus that appears when I execute my GMF diagram. I know I can do
my own menus using the org.eclipse.ui.menus extension, but what I'm
looking for is to change the "File", "Edit" etc. menus for others
designed by me. If I could't I'd like to hide them or something similar.