The Aqua scroll track and knob aren't displayed on Windows using ToT + 3.1.2 or 4.0dp1. Vertical is fine.
Created attachment 23735 [details] Patch to fix bug
Ignore the commenting out of the native controls pref. I will put that back in.
Comment on attachment 23735 [details] Patch to fix bug + /*if (Settings::shouldPaintNativeControls()) + return &windowsTheme;*/ Please don't check in commented out code. Otherwise, it looks good.
Fixed.