Specifying the Number of Undo and Redo Actions To specify the number of permitted undo and redo actions: From the Smart View ribbon, select Options, then select Advanced in the left panel. In Number of Undo Actions, specify the number of permissible Undo operations, 0 through 100. This is also the number of Redo operations permitted. Click OK. The setting takes effect after you refresh or perform a drill operation.