Special workspace quits when there's a fullscreen window in backgrounded workspace

[arbitrary-dev]

Special workspace quits when its window loses focus and there's a fullscreen window in backgrounded workspace behind it.

To reproduce:

1. Open a fullscreen window in Workspace 1 (WS1);
2. Switch to Special Workspace (WSS) with Win+S;
3. Open up a terminal, for an example;
4. Hover mouse from the terminal to the fullscreen window (from WS1) in a background;
5. WSS exits and focus switches to WS1.

Expectation:

No ability to interact with faded fullscreen window from ordinary workspace while being in a Special Workspace.