[jussij]

Some of the controls allow you to change their colors, but that is not true for all controls.

As an example consider the Win32 based wxWidgets library.

The developers state it can't be made to support 'dark mode' only because not all Windows controls allow for easy color changing:

https://forums.wxwidgets.org/viewtopic.php?t=45869

[rbanffy]

Implementing what's possible to implement and leaving the rest broken is pretty ok. Developers will avoid the broken controls or code replacement ones.