There is a bug in TOAD for Oracle 188.8.131.522 in which the menu is messed up after a connection is lost by external means such as a session timeout or network disconnect. Whenever such an event occurs, the menu appears to be the same, but clicking menu items does nothing. Hovering across the menu bar shows that the men items have been reduced to single letters. As shown in this screenshot:
The menu is restored after minimizing and maximizing the window.