SUMMARY In System Settings on the Quick Settings panel I can select light or dark theme. This changes the appearance of both Qt applications and Plasma. However, after logging out and logging in, Plasma is in dark mode again. Qt applications remember the mode correctly, and the settings panel also shows that the current theme is light. STEPS TO REPRODUCE 1. Set light theme 2. Logout, login 3. Plasma is dark again Plasma 5.22.4 on Fedora 34.
I was able to reproduce this issue in Plasma 5.22, but no longer can in 5.23 (dev version). What do you have set on the following pages in the Appearance section: Global Theme Plasma Style Colors
Global Theme: Breeze Plasma Style: Breeze Dark Colors: Breeze Light I haven't touched these before, just the Quick Settings. If I change Plasma Style to "Breeze (follows color scheme)", it seems to stays that way even after playing with the Quick Settings.
Thanks. Looks like the quick settings failed to change the global theme from Breeze to Breeze Dark. Cannot reproduce on git master though.
This was fixed in Plasma 5.24.