Created attachment 153339 [details]
kWin Support Info: Initial state, both screens enabled

SUMMARY

After making the secondary screen primary and disabling the main screen, some windows stuck on the disabled output:

In my case these were Firefox (Wayland native), Thunderbird, KSystemMonitor and Gajim.
Other opened applications, such as Systemsettings, KeePassXC and and Strawberry were correctly moved to the only enabled screen.

When I repeated it it changed a little, e.g. Thunderbird was now moved correctly. It seems somehow random though.

STEPS TO REPRODUCE
1. Two screens, applications opened on several VDs on the primary screen
2. In KScreen: Disable the output and make the secondary screen primary
3. Hit apply

OBSERVED RESULT
Clicking on some of the app's icons in the taskmanager shows an animation that the window becomes opened and minimized on the now disabled screen.
Re-starting the application "fixes" the issue.

EXPECTED RESULT
All apps correctly move to the only enabled primary screen.

SOFTWARE/OS VERSIONS
Operating System: openSUSE Tumbleweed 20221028
KDE Plasma Version: 5.26.1
KDE Frameworks Version: 5.99.0
Qt Version: 5.15.6
Kernel Version: 6.1.0-rc2 (64-bit)
Graphics Platform: Wayland
Graphics Processor: AMD Radeon RX 580 Series