Hello, this is my first post :o
I've done a search and didn't see this idea...
I think it'd be very useful for the layout editor to have a button that allows you to hide all the invisible items (bombs, traps, teslas...) so you could view the layout as an opponent would see it.
Better still, it could toggle between visible, invisible and 50% transparent.
(The 50% transparent would still allow the invisible items to be moved around.)

