return nsnsull;
return nsnull;
GetPopupSetFrame(nsPresContext* aPresContext){  nsIFrame* rootFrame =    aPresContext->PresShell()->FrameManager()->GetRootFrame();  if (!rootFrame)    return nsnull;  if (rootFrame)    rootFrame = rootFrame->GetFirstChild(nsnull);   nsCOMPtr<nsIRootBox> rootBox(do_QueryInterface(rootFrame));  if (!rootBox)    return nsnsull;  nsIFrame* popupSetFrame;  rootBox->GetPopupSetFrame(&popupSetFrame);  if (!popupSetFrame)    return nsnull;  nsIPopupSetFrame* popupSet = nsnull;  CallQueryInterface(popupSetFrame, &popupSet);  return popupSet;}