1

I often display one window on top of full screen window. Top level window is semi-transparent and sometimes it is also full screen.

Problem is: some games grab a mouse/keyboard and I do not like to ALT+TAB or CTRL+F<desktop_number>, because it disallow me to watch bottom window.

Solution is to allow to activate an window by key combination, without restack windows. One window is semitransparent currently.

Use cases:
1. Read e-book, while playing or watching videos
2. Use discord, while playing
3. Another possibility?

You will got point, if you allow to delegate only selected controllers to group dependent of selected group of windows, so I can use mouse in Stellaris and Keyboard in Okular.

Another use case:
3. Show game instruction on top of game window. Use scroll or keyboard to scroll PDF document and play game. For example: keybindings in older games are not changeable and described in handbook. Games like Mortal Kombat (1), Settlers (1). For mortal kombat I've got PDF, but for Settlers 1 I use web page with buildings description.