The undo manager of the context.
- iOS 3.0+
- macOS 10.4+
- tvOS 9.0+
- watchOS 2.0+
- Core Data
You can set the undo manager to
nil to disable undo support. This provides a performance benefit if you do not want to support undo for a particular context, for example in a large import process—see Core Data Programming Guide.
If a context does not have an undo manager, you can enable undo support by setting one. You may also replace a context’s undo manager if you want to integrate the context’s undo operations with another undo manager in your application.