mFocusListeners->AppendElement((void*)aElement);
XULCommandDispatcherImpl::AddCommand(nsIDOMElement* aElement){  NS_PRECONDITION(aElement != nsnull, "null ptr");  if (! aElement)    return NS_ERROR_NULL_POINTER;  if (!mFocusListeners) {    mFocusListeners = new nsVoidArray();    mFocusListeners->AppendElement((void*)aElement); // Weak ref to element.  }  return NS_OK;}