wxNotebook::GetThemeBackgroundColour() returns incorrect result when using high contrast

[vadz]

Ah I forgot to bring it up before it was fixed. It may be good to come up with a better solution here on Windows.

https://gitlab.com/kicad/code/kicad/-/issues/17262

Windows 10/11 has high contrast mode which alters the dialog colors. GetThemeBackgroundColor falls through to the white color on it as well.

Originally posted by @marekr in #25527

[vadz]

Note to self: this happens when using "high contrast black" mode, which is not "dark mode".

[vadz]

Unless I'm missing something (which is quite possible, of course), there is no way to get the colours used in high contrast modes using GetThemeColor(), so we're going to need to explicitly test for the high contrast mode to fix this.

Please let me know if anybody knows more about this/sees a better way to handle it.

[vadz]

Actually I take my words back, I think I did find a way to get the correct colour and it's rather simple, even if slightly hacky, please see #25545 and the commit auto-linked above.