What OS are you on? The top bar looks really bad on Windows 7, and apparently that's just how it is. On Windows 10 the entire top bar should change color based on theme. I don't know about other platforms.
I'm on Windows 8.1. And yes, the top bar looks like Windows' window color. I guess it's the same behavior as Windows 7. Oh well, I'll learn to live with it or install a custom theme (they work fine).