Getting to know the program > Palettes > History
History
This palette lists the actions taken on the current image, allows you to undo and redo adjacent or non-adjacent actions. Refer to the 'Edit' menu item for more information.
 The Undo All command allows you to undo all your actions.
 The Undo command allows you to undo your last action.
 The Redo command allows you to redo your last action.
 The Redo All command allows you to redo all your actions.
 The Reload Image command allows you to reload the original image.