I posted this at the end of the previous chain, but then noticed it had been marked as resolved, so figured I'd better repost.
Now I've found another weird thing about the latest update. In the Image Manager Extended, the popup url line has disappeared (see attached). Sometimes I need to have a picture showing on the page, but when you click on it another picture pops up. I've always been able to do this before in JCE by just putting a different url in the url field on the popup page. How do I do it now?