Created attachment 160011 [details]
Image showing the issues described above

SUMMARY
When running waydroid in multi-window mode, the decorations don't paint properly under kwin. The action buttons (close, maximise, minimise) are drawn, but no background is drawn. Shadows suggest that the window is being drawn smaller than expected: the outer edge of the shadow around the titlebar matches the outer edge of the rest of the window's content. (See attached image!)


STEPS TO REPRODUCE
1. Install waydroid, and enable multi-window mode ( waydroid prop set persist.waydroid.multi_windows true )
2. Run an android app. If necessary, switch to multi-window mode by pressing the F11 key
3. Note the corruption in the header.

OBSERVED RESULT
Titlebar area has no background drawn.

EXPECTED RESULT
Background should be a solid colour, as it is under mutter.

SOFTWARE/OS VERSIONS
Operating System: Fedora Linux 38
KDE Plasma Version: 5.27.6
KDE Frameworks Version: 5.107.0
Qt Version: 5.15.10
Kernel Version: 6.3.8-200.fc38.x86_64 (64-bit)
Graphics Platform: Wayland
Processors: 4 × Intel® Core™ i5-7200U CPU @ 2.50GHz
Memory: 11.5 GiB of RAM
Graphics Processor: Mesa Intel® HD Graphics 620