nsresult result = child->QueryInterface(kIFormControlFrameIID, (void**)&fcFrame);
nsresult result = child->QueryInterface(NS_GET_IID(nsIFormControlFrame), (void**)&fcFrame);
nsLabelFrame::FindFirstControl(nsIPresContext* aPresContext,                               nsIFrame* aParentFrame,                               nsIFormControlFrame*& aResultFrame){  nsIFrame* child = nsnull;  aParentFrame->FirstChild(aPresContext, nsnull, &child);  while (nsnull != child) {    nsIFormControlFrame* fcFrame = nsnull;    nsresult result = child->QueryInterface(kIFormControlFrameIID, (void**)&fcFrame);    if ((NS_OK == result) && fcFrame) {      PRInt32 type;      fcFrame->GetType(&type);      // buttons have implicit labels and we don't allow them to have explicit ones      if (!IsButton(type)) {        aResultFrame = fcFrame;        return PR_TRUE;      }      NS_RELEASE(fcFrame);    } else if (FindFirstControl(aPresContext, child, aResultFrame)) {      return PR_TRUE;    }    child->GetNextSibling(&child);  }  return PR_FALSE;}