Created attachment 173677 [details]
1-Fade ignores window in focus | 2-Except when both are in focus.

As the attachment shows, when only one window is in focus (tomato), and you hover the mouse over an window not in focus (potato), for some odd reason the fade effect roughly flashes your desktop, then the window starts fading in.
In the later part, when both windows are in focus, the fade effect works smoothly between them.

Not only its visually inconsistent, it could cause a headache if you have photosensitivity.
I believe the issue is that the fade effect ignores window in focus when another is not in focus, thus flashing the desktop as failsafe.

(This is different from #479086 , where I've asked for the deactivation of the effect)