How to add a checkbox to the menu item in WordPress backend that says "Make this a Mega Menu Container"? In my mind it should look something like this (Photoshop draft):
And when the box is checked instead of adding another standard ul > li DOM element a div container is added instead?
I have no idea how to approach this. I was planning to use walker to change the DOM for the menu, but how to "activate" the walker only for some menus - in this case the menus that I choose by that checkbox to be the mega menu?