[whatwg] WF2: setCustomValidity()

[Sean Hogan]

A question about the setCustomValidity method:
The spec states:

    "If the method's argument is |null| or the empty string, then the
    flag is reset (indicating that the control is valid)"

Does this mean that setCustomValidity(null) will always set 
"validity.valid" to "true"? 
Will it reset all the other validity error-codes to false? 
Or does customError over-ride all the other errors? 

cheers,
SDH