Hello,
Thank you very much for sharing the issue and I am very sorry for the experience!
As Ling suggested we need to know a bit more about your computer specs, driver status and whether this is file-related or not. I would also want to ask if you open Archicad with your Macbook Pro screen (not the external screen), does the issue happen?
Looking forward to hearing from you!
Best regards,
Minh
Minh Nguyen
Technical Support Engineer
GRAPHISOFT