Created attachment 129290 [details] Wayland session SUMMARY I'm not certain if there is an specific effect that is not being applied, but basically the Task Manager applet has a darker color (or contrast, translucency, I'm not sure) when I'm on a Wayland session. Also, to be honest, I'm not sure if that's the expected behavior, but I decided to report anyway. STEPS TO REPRODUCE 1. Have a NVIDIA GPU 2. Log in to a "Full Wayland" Plasma session 3. Notice the dark color contrast of Task Manager widget 4. Logout 5. Switch to a X11 Plasma session 6. Notice the much lighter color contrast on the Task Manager applet OBSERVED RESULT Darker color contrast on the Task Manager applet EXPECTED RESULT Color contrast to match in both Wayland and X11 SOFTWARE/OS VERSIONS Operating System: openSUSE Tumbleweed 20200611 KDE Plasma Version: 5.19.0 KDE Frameworks Version: 5.70.0 Qt Version: 5.15.0 Kernel Version: 5.6.14-1-default OS Type: 64-bit Processors: 4 × Intel® Core™ i5-3570K CPU @ 3.40GHz Memory: 7,7 GiB of RAM Graphics Processor: GeForce GTX 660/PCIe/SSE2 ADDITIONAL INFORMATION NVIDIA proprietary driver version 440.82 As far as I could tell, the colors are off only on Plasmoids, i.e. on Dolphin they match in both Wayland and X11 sessions.
Created attachment 129291 [details] X11 session
Seems to have the same issue with nvidia and wayland. I have a dark transparent theme with X11. But with a wayland session the theme become black with no blur and transparency. Only the desktop theme is affected,no issues with kwin or with a intel gpu. Sent a bug report also. Bug 426464 - No desktop transparent themes in wayland sessions.
I can reproduce this issue. I can also reproduce this issue in a X11 session, by using export KWIN_OPENGL_INTERFACE=egl export KWIN_COMPOSE=O2ES It looks like a bug related to NVIDIA EGL implementation, I think.
With nvidia, kwin had issues with detecting whether a surface has an alpha channel. It was fixed in 5.23. In 5.24, support for egl streams was dropped.