Force Opacity on Normal Windows breaks Desktop layer (permanent black, survives plasmashell restart) — Plasma 6.7.4, Iris Xe, Wayland
I'm using Fedora Linux 44 with KDE Plasma 6.7.4 on Wayland (Kernel 7.1.8, Qt 6.11.1) on a Dell Inspiron 15 5510 (Intel Core i5-11320H, Iris Xe).
Important background (a bug I discovered): Forcing opacity (Force opacity) via Window Rules on any Normal Window causes a solid black layer to appear instead of transparency on the desktop layer (plasmashell Desktop layer, layer-shell FirstLayer) — even after adding an explicit exclusion rule for plasmashell with higher priority ordering and a "Do not affect" value. Worse: this state is not fixed by restarting plasmashell (kquitapp6 plasmashell && kstart plasmashell), but requires removing the force-opacity rule and doing a full system reboot. This matches a documented category of bugs in KDE Bugzilla (
#366318 and
#449445) related to a stuck compositing state for plasmashell that only clears with a full reinitialization of kwin_wayland. I previously tried KWIN_DRM_NO_AMS=1, but it later turned out to be unrelated (it was a misleading coincidence with disabling the rules at the time of testing).
My goal: Create a genuine "frosted glass" effect (transparency + blur) on regular windows, while avoiding this bug entirely this time. I need:
1.An alternative method (not Window Rules force opacity) for achieving the glass effect — such as KWin's built-in Blur effect directly, or the external Force Blur effect — while avoiding any interaction with the desktop layer.
2.Confirmation of whether the built-in Blur effect in Desktop Effects (as opposed to Window Rules) structurally avoids this bug, since it doesn't force a new compositing state onto the Desktop window type.
3.Any precautions or correct settings ordering that prevents this bug from recurring on Iris Xe hardware.