I too have this problem, it shows up out of the blue.
It mostly seems to happen when I have to select multiple cells for any reason and then I cannot stop selecting them - but not always.
I have found that the zoom works some times, also a quick short term solution is to copy an empty cell and then paste it into another empty cell. It seems anything that refreshes the screen temporarily stops it.
I have also found, just leaving the window open and moving into another program for a few mintues (like typing in the tech forums) will sometimes resolve the problem. But I have tried closing all of my excel windows and completely exiting the program
and comes right back up.
I also tried the F8 and it did not work.