While building a craft, my game got stuck in designer mode. I was able to build like normal, but, I could not save my craft, upload it, report a bug, or launch it. I was also unable to exit the game so I had to kill it through task manager.
I did however save the thing I was working on as a subassembly. This seemed to work until I tried to use the assembly and the game got stuck in Designer Mode again.
I am not sure how to get the game to repeat this without the subassembly I made.