nsCOMPtr<nsITextControlFrame> textControlFrame(do_QueryInterface(formControlFrame));
if (formControlFrame){ nsITextControlFrame* textControlFrame = nsnull; CallQueryInterface(formControlFrame, &textControlFrame);
nsHTMLTextAreaElement::SetSelectionStart(PRInt32 aSelectionStart){  nsCOMPtr<nsIFormControlFrame> formControlFrame = getter_AddRefs(GetFormControlFrame(PR_TRUE));  nsCOMPtr<nsITextControlFrame>    textControlFrame(do_QueryInterface(formControlFrame));  if (textControlFrame)    textControlFrame->SetSelectionStart(aSelectionStart);  return NS_OK;}