I couldn't find any concept better than: End editing before undoing.
However, I got rid of the code smell of my original solution. Instead, I
register the window controller to receive it's document's undo manager's
NSUndoManagerWillUndoChangeNotification and
NSUndoManagerWillRedoChangeNotific
App has an NSTableView; each row represents a managed object in
NSPersistentDocument.
• User inserts a new object.
• Object is inserted with -[NSEntityDescription
insertNewObjectForEntityForName::].
• New row appears in the table.
• New row's "Name" column field editor becomes first responder, s
