A row of square black dots has begun to appear in one of my Word documents. I can't select them but they do print. At first I thought that switching Markup off cleared, and thought they were non-printing characters, but after a short delay they return.
I'm attaching a screenshot. Any thoughts?
I'm actually helping my mother solve this problem. She's using a Mac with an older version of Word. I'm using Word 2008, but am still getting the same problem.