You have 2 options:
1) Using MAMEWAH Config or notepad, re-map the MENU_SHOW key in your MAMEWAH controller file to a key that's not mapped to any of your buttons (this is the safest method, but you have to have your keyboard out whenever you want to do MAMEWAH maintenance).
2) Press Left ALT and 2 (the default) to lock the menus.
-sab