Thick Plus Shaped Mouse Pointer

One of my desktop publishers is experiencing a problem with her mouse pointer inside of Word 2003 that I've never seen before. Occasionally her pointer takes on the shape of a thick, black plus sign. It resembles the pointer you'd see when inserting a drawing or table, but the lines are much thicker. It appears out of the blue and disappears similarly, and it behaves like a normal pointer. If she moves the pointer off the document or between options in her toolbars, the standard arrow pointer returns. Additionally, the pointer returns to normal if she saves her document.

This is not necessarily a huge problem, but I'm still very interested in why it's happening. Any info would be much appreciated!