Thanks for the suggestion, Paul, but unfortunately, that didn't work either. Since you mentioned hidden text I went to File>Option>Display and selected hidden text but that didn't do anything.

Another symptom: When I press Ctrl-End, I don't go to the end of the document, but when I press Ctrl-Home I go to the top. There's something weird at the bottom of this document.

Can I send it to you and you can see if you can figure it out?