Created attachment 138631 [details]
Kate appearance with global Breeze theme enabled

In some applications (the only one I can remember at the moment is Kate), no matter what is selected in system settings, a specific variant of the Breeze theme will always be used. Specifically, the application will use the dark title bar, even though recent KDE changes made a light titlebar the default.

I'm including two screenshots to illustrate the problem, one with the Breeze global theme set, one with the Breeze Dark global theme set. Kate was closed before each theme change. You'll notice that Kate appears basically the same in each case, with the only noticeable change being to the menu bar. The system settings window in the background indicates the correct colors for the chosen theme.

This one should be trivial to reproduce (where it occurs): just set the system colors theme to anything except Breeze, and see if Kate uses the chosen colors.

The bug is pretty annoying because it makes Kate more-or-less unusable on my system.

SOFTWARE/OS VERSIONS
Linux: Arch Linux x86_64 5.12.2-arch1-1 
KDE Plasma Version: 5.21.5
KDE Frameworks Version: 5.82.0
Qt Version: 5.15.2

ADDITIONAL INFORMATION

Both screenshots are tagged with an ICC profile that should enable you to see the colors as they actually appear on my desktop when the image in viewed in a color managed viewer on a calibrated screen. They will likely appear unexpectedly saturated. This is because of a different bug, which breaks KDE's color schemes on my desktop: https://bugs.kde.org/show_bug.cgi?id=427667