Input disabling in the "More" menu on windows context menu

It would be really nice if I could disable inputs going to a certain window. One use-case for this for example would be having a fullscreen application in the background at all times, but not accepting input, such as for a video. Or maybe to make sure you don’t scroll away from some important information by accident.

To be more precise, I am talking about this context menu:

i know from experience that if you get rid of the titlebar and frame you will have a hard time getting back to this menu.

I wouldn’t say so since you can access it from the panel, and to make it come visible you can just open the application launcher with super. I see the issue though, and I think that could be resolved by maybe implementing a Super + Right Click that opens the window’s context menu maybe?