Icons and shortcuts
The Undo command contains support for unlimited levels of Undo. Every action can be undone and it is possible to undo one command after another. The Undo history is retained after using the Save command, enabling you go back to the state the document was in before you saved your changes. You can step backwards and forwards through this history using the Undo and Redo commands (see Redo command below).
The Redo command allows you to redo previously undone commands, thereby giving you a complete history of work completed. You can step backwards and forwards through this history using the Undo and Redo commands.