By this definition, it's ambiguous what needs to happen to the documentElement's undoScope attribute, since it doesn't have an element ancestor. I think we should just clarify that in that case, the value is "true", and the undoManager attribute is the same as document.undoManager.
Maybe those should be merged? That way we do not need to extend Document.
-- Anne van Kesteren http://annevankesteren.nl/
