*_retval = new nsHTMLSelectListAccessible(this, mDOMNode, mPresShell);
nsCOMPtr<nsIDOMNode> last; mDOMNode->GetLastChild(getter_AddRefs(last));  *_retval = new nsHTMLSelectOptionAccessible(this, last, mPresShell);
NS_IMETHODIMP nsHTMLSelectWindowAccessible::GetAccLastChild(nsIAccessible **_retval){  *_retval = new nsHTMLSelectListAccessible(this, mDOMNode, mPresShell);  if ( ! *_retval )    return NS_ERROR_FAILURE;  NS_ADDREF(*_retval);  return NS_OK;}