For @proteus-dev and anyone else seeing Window Not Responding, we are actively trying to fix this issue and could do with some help.
Please read my comment here, and reply in the linked thread - hopefully with the right information, we can get this fixed quickly!
Due to the range of issues in this thread, I will lock it for now, but please feel free to post a new post in Bug Reports with your specific issue, and @ me directly so I can jump in quicker!