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The Undo command reverses the last action you took. DAZ Studio supports multiple undo actions, meaning that you can delete many prior actions. The undo operations occur in the reverse order, beginning with the most recent action. Undo actions apply only to those you performed in the current session. In other words, if you create a scene, save it, then close it, you will not be able to undo your previous actions when you reopen the file.
This menu item will remain grayed-out until you perform your first action in a scene. Afterward, you can use one of the following methods to perform an Undo action: