Start Pinball FX2. Click or press Enter to get to the table grid screen. Wait until logged in (if you are connected to the Internet), then simply wait for approximately 30 seconds, without clicking the mouse or pressing any keys. The grid clears, going to a 4x3 grid configuration. Tables can't be accessed, unless the game is restarted, or the Restore Tables button (shopping cart icon) is clicked.

This bug may be related to, or the same one as my previous post: Tournament Button / Update Bug