Setting the Framebuffer target is the same as setting the read and draw buffer targets independently, just with one API call instead of two. So we want to do this check because if either the read buffer or draw buffer are the handle we're getting, we don't want to use the Framebuffer target. Instead it'll fall down to one of the other cases to update one of the two targets independently.

This is in Windows 7 SP1 on my MacBook Pro using Bootcamp. It's got an Intel Iris 5100 chip in it and whatever drivers Apple/Windows provided (Apple installed some during setup, but Windows maybe have updated them at some point with Windows Update).