SUMMARY The panel styling for Adaptive Transparency overrides the 'opaque' panel styling Plasma is meant to use when there's no compositor, making the compositorless panel in KDE Plasma use the 'solid' styling when a window is maximised, which to put it simply IS NOT meant to occur at all as 'solid' IS NOT meant for use without a compositor by design. STEPS TO REPRODUCE 1. Turn on Adaptive Transparency 2. Turn off the Compositor 3. Maximise a window OBSERVED RESULT 'solid' styling is used. EXPECTED RESULT 'opaque' styling stays used. SOFTWARE/OS VERSIONS Windows: macOS: Linux/KDE Plasma: KDE neon Developer Edition Unstable 5.24.80 (available in About System) KDE Plasma Version: 5.24.80 KDE Frameworks Version: 5.92.0 Qt Version: 5.15.3 ADDITIONAL INFORMATION You can easily check this bug using this theme: https://github.com/feren-OS/feren-theme/tree/work/2022-redesign/plasma/feren-coloured (may be broken unless you also put https://github.com/feren-OS/feren-theme/tree/work/2022-redesign/plasma/feren in the same folder) (the theme has a grey 'opaque' panel, but otherwise uses a darkened version of the colour scheme's Selected Background for the panels' colour - just panels for now, though, as menus are to be done - irregardless you can easily see the bug with this theme)
A possibly relevant merge request was started @ https://invent.kde.org/plasma/plasma-desktop/-/merge_requests/1251
Git commit 20cb61789fad5e9ac5f155a841d2c686a80cf875 by Nate Graham, on behalf of Niccolò Venerandi. Committed on 16/11/2022 at 17:38. Pushed by ngraham into branch 'master'. Panel: Avoid setting solid background when compositing is disabled The svg with "solid/" style would override "opaque/" which is preferred when compositing is disabled. Since we don't have transparent panels when compositing is disabled, we don't need adaptive transparency at all. FIXED-IN: 5.26.4 M +5 -1 desktoppackage/contents/views/Panel.qml https://invent.kde.org/plasma/plasma-desktop/commit/20cb61789fad5e9ac5f155a841d2c686a80cf875
Git commit 3e24f14d873b7d753fc848fb8fcafd2e1c83b9c8 by Nate Graham, on behalf of Niccolò Venerandi. Committed on 16/11/2022 at 17:44. Pushed by ngraham into branch 'Plasma/5.26'. Panel: Avoid setting solid background when compositing is disabled The svg with "solid/" style would override "opaque/" which is preferred when compositing is disabled. Since we don't have transparent panels when compositing is disabled, we don't need adaptive transparency at all. FIXED-IN: 5.26.4 (cherry picked from commit 20cb61789fad5e9ac5f155a841d2c686a80cf875) M +5 -1 desktoppackage/contents/views/Panel.qml https://invent.kde.org/plasma/plasma-desktop/commit/3e24f14d873b7d753fc848fb8fcafd2e1c83b9c8