AntTweakBar on the Mac

At first when you launch CView, the tweakbar behaves normally.  This bug only manifests itself when you go into fullscreen mode by pressing 'f'.  After you do that, the tweakbar never recovers, and it's messed up from that point forward until you restart CView.  The problem looks like the drawing position is not the same as the position that is used for mouse input -- there is some weird offset.
