Contents of the Edit menu
This command can be accessed from an image menubar as Ctrl-Z.
-> , or by using the keyboard shortcut"Undo" allows you to revert an image back one step in the drawing or editing process. Almost anything you do to an image can be undone in this way. Further undo operations may be performed according to the number of undo levels configured in the Environment page of the Preferences Dialog. See the section on Undoing for more information about GIMP's very sophisticated "undo" functions.