u/Bot04

I think starting yesterday after a game I was playing crashed and took the Steam client down with it, my computer stopped displaying X11 apps on fullscreen correctly.

Some applications are just displayed behind the panel and some also have the border and title bar show up, Half-Life (example in the image) starts not even maximized. However, if I right-click the window border and activate fullscreen manually it works as intended, but I'd have to do this every time I open an application.

Seems to not be a problem with Proton, since this also happens for native X11 apps (eg: Factorio with preferred video driver set to X11)

I'm running CachyOS with KDE Plasma on Wayland.