I was just starting a simple definition. I hit he expand window button, the green one, and grasshopper went went full-screen but with the Apple bar still showing. i hit the green button again to go into real Full-screen. Then with Option key I went back to almost full screen with just the Apple bar, i am not sure of it’s technical name. I then grabbed a corner arrow to resize the grasshopper window manually. This is when i got this exception and everything was greyed out, so I had to force quit Rhino WIP.