I was using Grasshopper on my MacBook, and I must have clicked something wrong, so the Grasshopper window became a little blurry and I couldn’t see anything in the view tap.
I am attaching the Grasshopper file in question. Thank you in advance.
Try hitting the ESCAPE key. I think you must have inadvertently clicked on the preview selection button which lets you create a lasso style shape and it will then only preview the objects within that shape. That odd angled shape at the end was the lasso shape you selected (by accident) and thus nothing was showing. You can remove the selection by hitting the ESCAPE key.