Bug 495169

SUMMARY

kwin_x11 sometimes stops responding to or bubbling inputs after moving/resizing/minimizing/restoring Steam window.

Interacting with UI elements within the Steam app don't seem to trigger the issue.

When the issue occurs, keyboard presses and mouse clicks (incl scroll) do nothing either within individual app windows/panels/widgets or with kwin elements like titlebars, although it appears that apps can still perform graphical updates since videos and animations et al continue to work normally.

It seems like dragging a window titlebar and _then_ pressing a keyboard key can _sometimes_ cause a momentary update, but kwin then returns to the stuck state.

This erroneous state affects all windows/panels/widgets/etc on the entire desktop, not just Steam.

Killing Steam or restarting kwin_x11 fixes things - although usually I have to jump to a console to do this due to the nature of the issue.  
Jumping to a console and returning to Xorg without poking anything does not resolve the issue, unless Steam happens to crash due to graphics reset which it does sometimes.

There doesn't appear to be any unusual CPU usage.

The mouse cursor still moves normally, and there's no indication that clicks are simply going to an incorrect XY location.

STEPS TO REPRODUCE
1. Open Steam Desktop Client for Linux
2. Move/resize/minimize/restore Steam window several times

OBSERVED RESULT

kwin_x11 stops responding to key/mouse input events properly, and does not pass events to app windows either.

EXPECTED RESULT

kwin_x11 continues working normally.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma:  Gentoo Linux 2.15
KDE Plasma Version: 6.1.5
KDE Frameworks Version: 6.6.0
Qt Version: 6.7.2

ADDITIONAL INFORMATION

I'm aware that this may not be enough info to fix anything, but I'm unsure of appropriate debugging steps that would be most helpful - feel free to ask me to reproduce the issue and perform specific debugging tasks.

The issue seems to be reasonably easy for me to reproduce - which is kinda frustrating when interacting with steam, but probably good for debugging.

I had a look for existing bugs, but didn't find any that seem to match.

This issue did not occur in KDE5.

Compositing is of course enabled.