The Undo feature can be turned off or on at any time by selecting the Edit menu's Undo On/Off option or by clicking the button located in the upper right of the Undo History window.


It sometimes can be beneficial to temporarily turn off the Undo feature when making a series of minor changes to a large image. This will speed up the process as you will not have to wait for PixelNEO to update the undo buffer after each edit. When finished with the changes, the Undo feature can be turned on again.