model = do_QueryInterface( nsXFormsUtils::GetModelAndBind(mElement, nsXFormsUtils::ELEMENT_WITH_MODEL_ATTR, getter_AddRefs(bindElement)));
nsCOMPtr<nsIModelElementPrivate> model = do_QueryInterface(modelNode);
nsXFormsOutputElement::WillSetAttribute(nsIAtom *aName, const nsAString &aValue){  if (aName == nsXFormsAtoms::bind || aName == nsXFormsAtoms::ref) {    nsCOMPtr<nsIDOMElement> bindElement;    nsCOMPtr<nsIModelElementPrivate> model;    model = do_QueryInterface(        nsXFormsUtils::GetModelAndBind(mElement,                                       nsXFormsUtils::ELEMENT_WITH_MODEL_ATTR,                                       getter_AddRefs(bindElement)));    if (model)      model->RemoveFormControl(this);  }  return NS_OK;}