The disappearing cells could be a bug I've been trying to track down since version 3.0. In version 3.3, I changed the code to make sure an error no longer pops up since I couldn't reproduce the problem. And since I can't reproduce it, I'm not certain what will the result will be but I suspect the disappearing cells are exactly what would happen. Unfortunately I still can't reproduce it even with your layout. Might be interconnected with the tournament, but I can't say. If you experience it again, please save the tournament WITH the layout and send that to me.