Bug 510774

Created attachment 185894 [details]
What it looks like

SUMMARY


STEPS TO REPRODUCE
1. Go into settings, enable windows 9x application style
2. Go into colors and make a theme or change an existing one's Common Colors > window background to be less than 25, 25, 25

OBSERVED RESULT
ugly white highlights on all windows, as if high contrast was activated in a real windows environment

EXPECTED RESULT
It stays dark, like at 25,25,25 and above

Operating System: CachyOS Linux 
KDE Plasma Version: 6.4.5
KDE Frameworks Version: 6.19.0
Qt Version: 6.10.0
Kernel Version: 6.17.3-3-cachyos (64-bit)
Graphics Platform: Wayland
Processors: 16 × AMD Ryzen 7 5800X 8-Core Processor
Memory: 32 GiB of RAM (31.3 GiB usable)
Graphics Processor: NVIDIA GeForce RTX 3070 Ti
Manufacturer: Micro-Star International Co., Ltd.
Product Name: MS-7C56
System Version: 2.0

ADDITIONAL INFORMATION
This is intentional according to the 'reverse' and 'invert' lines in https://invent.kde.org/qt/qt/qtbase/-/blob/dev/src/widgets/styles/qwindowsstyle.cpp, but should be changed or have an option to disable. Other application styles have the ability to change their behavior with the pencil icon on the options menu, but ms windows has none and could use one here, probably more.