I'm getting an endless number of pop-ups stating, "OnGrid Tool -- Can't modify this cell". What's going on?

This can happen when double-clicking a blue link. Please single-click blue links next time.

The number of pop-ups is actually limited; to get rid of them simply keeping clicking "OK" or press Enter on your keyboard until they go away.

There's a chance that the blue link originally double-clicked disappears. In such case, try restarting the OnGrid Tool. If this doesn't work, please contact Technical Support.