According to MSDN on SystemColors.ActiveCaption:
Gets a Color structure that is the color of the background of the active window's title bar.
I'm finding that no matter what theme I have set in Windows 8, in Visual Studio this color is always the same (some shade of blue).:
In reality, my windows ActiveCaption is a shade of green:
So, why the difference? Where is Visual Studio pulling the ActiveCaption color (or the InactiveCaption, or any of the other system colors for that matter) if this value never changes?