Incompatible -setActionName Behavior

[aksuska]

NSUndoManager apparently ignores setActionName: calls when undo registration is disabled; GCUndoManager does not. I prefer NSUndoManager's behavior, which allows me to shut off registration at a high level, and avoids having to test enabled state every time I want to set the action name. I don't know whether simply inserting a check in -[GCUndoManager setActionName:] is sufficient, but that would be my recommended fix if it is reliable.