Multi-Level Undo/Redo
A whole series of edit operations can be undone using the Undo Item in the Edit Menu. If you go to far or just want to get back to a later edit, choose the Redo Item in the Edit menu.
The number of Undo commands is only limited by the first editing operation (Cut, copy, paste or delete) to occur after the Edit File was opened. This also applies to the Edit file that is opened following a Record operation. The Redo simply retraces the Undo steps.
Since edit operations do not apply to fader operations, Undo and Redo do not effect the Fader history.
You can also use the command key equivalents, command-Z for Undo and option-command-Z for Redo.