Window focus blocked at startup under X.org
Description
At startup, once I logged in (X.org), I open a few regular apps (like Firefox, File, or Terminal) and after a few seconds the focus gets blocked on one window. It happens like 80% of the time.
First symptom: (and the easiest way to see it) when I throw my cursor in the top-left corner, I can see the blue wavy FX thing, but the dashboard is not displayed.
Second symptom: if I click on another window in the background, It isn't brought to the front. I can Alt-Tab, and the other app comes to the front, but if I click on it, the click is dispatched to the focus-blocked window.
I made a video, please enable the subtitles for more info on what's happening: https://www.youtube.com/watch?v=ZkeRec9eiVA
Notes
I got it since.. I don't know.. 3 years? Right now I'm riding Fedora 28, but I had the bug in Fedora 27, 26, 25, 24, and maybe Manjaro and Arch as well... As far as I can remember, I've had this bug (even if I changed my hardware almost completely during this time span).
Workaround
To fix the bug, for the session, I press Ctrl-Alt-F3, then then I go back to my X.org session with Ctrl-Alt-F2. The windows kinda get redrawn and after that it works as expected.
It also works better with wayland, but I have some applications that don't work well with it, so for now I got no other choice than using X.org.