tomseys said:
Doing this does gives title bars the accent color but it trashes the taskbar and the start menu and everything else...
Actually, to be fair, doing that in 1809 doesn't give the same accent color to the title bars that happens normally in 1803 since it appears to color title bars #298ECC. The title bar color in 1803 is #26A6F2 (apparently based off of color #298FCC). You can customize it to this 1803 title bar color but then you have the other problem when you have start, taskbar and action center selected in addition to the title bars to have accent color applied to, and that is most everything is made the lighter color and you lose contrast.

I've now gone back to 1809, and applied my userChrome.css file + light theme to Firefox and did the same thing to Thunderbird and now they both look exactly like 1803. I think I've now gotten used to the darker title bars (#06476F vs #26A6F2) of 1809 on everything else which I deal with much less than FF and TB so for me this is really no longer an issue. Curious though to see if they will correct/switch this new much darker title bar color back to the way it was or if this is a new direction/permanent change. My guess is it is a bug/non intentional but then again who knows.