virtual nsresult DragMove(nsIDOMEvent* aMouseEvent) { return NS_OK; }
nsListControlFrame::DragMove(nsIDOMEvent* aMouseEvent) { NS_ASSERTION(aMouseEvent, "aMouseEvent is null.");   UpdateInListState(aMouseEvent);  if (!IsInDropDownMode()) { PRInt32 selectedIndex; if (NS_SUCCEEDED(GetIndexFromDOMEvent(aMouseEvent, selectedIndex))) {  if (selectedIndex == mEndSelectionIndex) { return NS_OK; } nsCOMPtr<nsIDOMMouseEvent> mouseEvent = do_QueryInterface(aMouseEvent); NS_ASSERTION(mouseEvent, "aMouseEvent is not an nsIDOMMouseEvent!"); PRBool isControl; #if defined(XP_MAC) || defined(XP_MACOSX) mouseEvent->GetMetaKey(&isControl); #else mouseEvent->GetCtrlKey(&isControl); #endif  PRBool wasChanged = PerformSelection(selectedIndex, !isControl, isControl); mChangesSinceDragStart = mChangesSinceDragStart || wasChanged; } } return NS_OK; }
  virtual nsresult DragMove(nsIDOMEvent* aMouseEvent) { return NS_OK; }