Undo and History

A standard feature of both the Mac and Windows operating systems is Undo. After you perform an action in just about any program, if you want to undo that action you can simply choose Edit > Undo or press Cmd/Ctrl-Z. If you decide that you want to restore the edit, just Undo again.

In addition to allowing you to back out of a bad edit, Undo provides you with a quick and easy way to see a before-and-after view of a specific effect. Repeatedly pressing Cmd/Ctrl-Z lets you quickly toggle your last edit on and off.