The easiest way is to simply resize or change the style of the window frame.
Highlight the WindowFrame object and resize it until the visual borders match the green outline. Then you'll probably have to expand WindowFrame and resize LowerTabBkg so it doesn't cover the exp bar.
Of course, my preference is to simply change the RStyleDefault property of WindowFrame.Frame to
/Framestyles.single_pixel and remove the RStyleDefault property from WindowFrame.Bkg.
