The title bar white in dark theme, please fix

[imagineer]

I'm a long term XNView Classic user and just recently dipped into the XNView MP for some conversion options and found that I prefer the dark theme on it better, but the white title bar is an eyesore. I've read mixed views whether the color is possible to change in Windows or not. Not even changing the default app theme of Windows 10 64-bit Pro to dark didn't change the title bar into dark. I tried also the suggested qt.conf tweaks, but they didn't change a thing, the title bar just remained white. I'd wish this was given serious attention by the development and an attempt to fix it.