SUMMARY Firefox Windows shadows frequently show as black bars with KWIN_USE_OVERLAYS=1. STEPS TO REPRODUCE 1. install official firefox release (in my case, on KDE Neon via the official Firefox apt repo 2. open firefox and make it not fullscreen 3. click onto another window 4. wait a few seconds and then click back and observe black bars where shadows should be (this is most common during video playback in firefox but can occur on any page with enough time) OBSERVED RESULT black bars where the shadows should be EXPECTED RESULT normal shadows SOFTWARE/OS VERSIONS Operating System: KDE neon User Edition KDE Plasma Version: 6.5.0 KDE Frameworks Version: 6.19.0 Qt Version: 6.9.2 Kernel Version: 6.14.0-34-generic (64-bit) Graphics Platform: Wayland Processors: 12 × AMD Ryzen 5 7640U w/ Radeon 760M Graphics Memory: 16 GiB of RAM (14.9 GiB usable) Graphics Processor: AMD Radeon 760M ADDITIONAL INFORMATION Device: AMD Framework 13
I can't replicate that here. Please get the output of drm_info from when the black bars are visible.
Sure thing. A bit hard to obtain that information since entering another window or another window update can cause the black bars to disappear. I was able to obtain it by activating the command `sleep 10; drm_info > drm_info.txt` minimizing the terminal, then interacting/moving/resizing firefox window until the black bars are visible (before the 10 second sleep was up) then just waiting for the command to execute.
Created attachment 186871 [details] requested drm_info when black bars are visible
Created attachment 186872 [details] 2nd drm_info output incase I messed up the timing in one
A possibly relevant merge request was started @ https://invent.kde.org/plasma/kwin/-/merge_requests/8443
Git commit f83accd60acb1f7c074b7a37724a5315819e59c6 by Xaver Hugl. Committed on 18/11/2025 at 12:45. Pushed by zamundaaa into branch 'master'. scene/workspacescene: don't put non-opaque items on an underlay Otherwise they get blended with black, instead of the scene below them. M +5 -0 src/scene/workspacescene.cpp https://invent.kde.org/plasma/kwin/-/commit/f83accd60acb1f7c074b7a37724a5315819e59c6
Git commit 6a6378feeeccc3767051dabd1691596e74236861 by Xaver Hugl. Committed on 18/11/2025 at 14:52. Pushed by zamundaaa into branch 'Plasma/6.5'. scene/workspacescene: don't put non-opaque items on an underlay Otherwise they get blended with black, instead of the scene below them. (cherry picked from commit f83accd60acb1f7c074b7a37724a5315819e59c6) Co-authored-by: Xaver Hugl <xaver.hugl@kde.org> M +5 -0 src/scene/workspacescene.cpp https://invent.kde.org/plasma/kwin/-/commit/6a6378feeeccc3767051dabd1691596e74236861