Hi Paul, thanks for reporting back with the fix - yes, antialiasing would mess up part of the interaction with the video card that involves selection. But I thought that I had requested that Direct3D turn off anti-aliasing for the particular operations that involve selection (which involves a rendered display that you don't see directly on the screen).

I'll double-check that when I get back from SIGGRAPH. It also may be a quirk in the video driver that it is not honoring a request for no antialiasing for one piece of processing...

- Michael