The lack of that was one of the most baffling things about the Win10 UI --- especially when you read about what they did:
https://www.howtogeek.com/222831/how-to-get-colored-window-t...
Microsoft chose to force white title bars in an odd way. In the uDWM.dll theme file in Windows, there’s code that looks at the current theme file name and compares it to “aero.msstyles” — the default theme file. If it matches, Windows ignores the color specified in the theme file and sets the color to white.
Someone at MS thought it would be a good idea to deliberately break title bar colouring by checking for a hardcoded theme filename. It wasn't a bug, it was an active decision to do such a "hack", and presumably others who reviewed the code were completely fine with it. Besides the completely stupid decision to force titlebars to be uncoloured, it's well deserving of a WTF!?