Compact menu with label and sprcial button clasd

How can i add the start label text to the compact menu and specify a custom css class to it. I know thats its possible in xfce but mate is more robust on faster hardware so ..? Its absolutely necessary to let it look like qvwm or fvwm95 or icewm or ylmf os or startos or ..
Any idea on how to fork the compact main menu so that it accepts wider buttons?