Created attachment 160050 [details] Flatseal under X11 SUMMARY *** NOTE: If you are reporting a crash, please try to attach a backtrace with debug symbols. See https://community.kde.org/Guidelines_and_HOWTOs/Debugging/How_to_create_useful_crash_reports *** STEPS TO REPRODUCE 1. Install Flatseal, (GTK/Gnome 44 application) from flathub.org, (via Discover) 2. Open Flatseal in a Plasma 6 Wayland session after installation. 3. Open Flatseal in a Plasma 6 X11 session after installation. 4. Compare how much poorer fonts look in Plasma 6 Wayland session. OBSERVED RESULT Fonts looked fine in X11, but look thin and distorted under Wayland. EXPECTED RESULT Fonts should look "normal" under Wayland, as well. SOFTWARE/OS VERSIONS Windows: macOS: Linux/KDE Plasma: (available in About System) KDE Plasma Version: 5.27.80 KDE Frameworks Version: 5.240.0 Qt Version: 6.5.1 ADDITIONAL INFORMATION Tried to screenshot the difference between how Flatseal looks under X11 and Wayland, but as I filed in bug #471874, screenshotting in Wayland sessions doesn't seem to be working properly yet, so will just attach what Flatseal looked like in X11, (if you want to see what the Wayland screenshot looked like, feel free to check bug #471874).
This is a client issue not a kwin one. Report to GTK. You may find installing the gtk portal fixes it.