I don’t think I did, honestly it’s so long ago now I can’t really remember but I just had a look at the relevant project and can’t see any code relating to it.
I believe that the menu items have a class menu-item-depth-0, menu-item-depth-1, etc. So you could add some custom CSS to the WordPress admin that hides the extra fields then shows them at a specific depth however this is a bit of a hack as the fields will still exist and will still save values you just won’t see them when editing.
