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# NSDocument.ChangeType.changeUndone

Decrement change count.

```
case changeUndone
```

## Discussion

A single change has been undone. For example, the built-in undo support of [`NSDocument`](/documentation/AppKit/NSDocument) passes this value whenever a document receives an <doc://com.apple.documentation/documentation/Foundation/NSNotification/Name-swift.struct/NSUndoManagerDidUndoChange> from its own undo manager.

---

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