Bug 498642

SUMMARY
If you apply a new theme, say going from Breeze light to Breeze dark and select to also change the desktop and window layout the windows currently open will stay open but the wallpaper will get permanently stuck at a black screen and never reload. Logging out (by pressing the power button) does not work. Rebooting or shutting down the system (either by pressing the power button or by switching to a tty) will simply hang forcing the user to force shutdown by holding the power button.

STEPS TO REPRODUCE
1. Choose a new theme in the system settings
2. Select "desktop and window settings" 
3. Click "Apply"

OBSERVED RESULT
The wallpaper and panel vanish and a black screen appears with only a mouse cursor and whatever windows were currently open, you can switch to a tty but the plasma session is locked up and will not stop even if the system sends a shutdown or reboot signal, leading to the user needing to hard reset.

EXPECTED RESULT
The theme should apply and not lock up the session

SOFTWARE/OS VERSIONS
(available in the Info Center app, or by running `kinfo` in a terminal window)
Linux/KDE Plasma: Arch Linux
KDE Plasma Version: 6.2.5
KDE Frameworks Version: 6.10.0
Qt Version: 6.8.1

ADDITIONAL INFORMATION
Kernel: 6.12.0-arch1-1 (64 bit)
Session type: Wayland
Processor: 12th gen Intel Core i5-12500H
RAM: 16GB (system reports 15.3)
GPU: Mesa Intel Iris Xe (however there is an NVIDIA RTX 3050M but it is not rendering the plasma shell)
Theme: breeze-dark Qt