Created attachment 173046 [details]
Apps interfaces examples, with and without KDE as desktop

SUMMARY
Some applications are not correctly applying colors is XDG_CURRENT_DESKTOP is not set to kde. I encountered this under Gentoo and Debian 12, using botyh Hyprland and i3. I had this problem for Dolphin, Okular, Ark, KColorChooser KCharSelect, KDE PartionManager, and other; in short almost all kde apps.
Most of those apps just do not follow the KDE theme, while other do it partially. Most of the time it is a minor inconvenience, but for other (Dolphin in specific) it is horrible.

STEPS TO REPRODUCE
1. Set Plasma theme to a dark one (easier to see differences then)
2. Install Dolphin
3. Launch Dolphin with XDG_CURRENT_DESKTOP != kde

OBSERVED RESULT
Themes are not respected (see attachments)

EXPECTED RESULT
Themes should be respected

SOFTWARE/OS VERSIONS
Operating System: Gentoo Linux 2.15
KDE Plasma Version: 6.1.4
KDE Frameworks Version: 6.5.0
Qt Version: 6.7.2

ADDITIONAL INFORMATION
I also reproduced this behaviour under plasma with the command 'XDG_CURRENT_DESKTOP=dqbzha dolphin'
I also had the dolphin problem under plasma 5 (and probably the others too, but I do not remember)