New
#11
I was looking into this recently, for my Win7 Aero theme.
It took me a while as I couldn't find the answer online, so I will share it in this old thread.
You can use a little app called Win7 Aero Square Corner Patcher (attached).
Or as I prefer, modify the Shadowless.FrameTop and Shadowless.FrameBottom with Windows Style Builder.
When using ASCP, the corners were sharp, but the rounding "shadow" was still visible, in my case (theme).