JavaScript must be enabled in order to use this site.Please enable JavaScript in your browser and refresh the page. SET UNDO Used to turn Undo (action) on or off. SET UNDO [ OFF | ON | TOGGLE ] Note: When Undo is turned off, the contents of the undo buffer are discarded. Thus, previous operations cannot be negated even after Undo is turned back on. To Toggle Undo To Enable Undo To Disable Undo Parent topic: Utilities