if (NS_OK == mParent->QueryInterface(NS_GET_IID(nsIScrollableView), (void **)&par)) {
if (NS_SUCCEEDED (mParent->QueryInterface(NS_GET_IID(nsIScrollableView), (void **)&par))) {
void CornerView::Show(PRBool aShow, PRBool aRethink){  if (mShow != aShow)  {    mShow = aShow;    if (mShow == PR_TRUE)      mViewManager->SetViewVisibility(this, nsViewVisibility_kShow);    else if (mShowQuality == PR_FALSE)      mViewManager->SetViewVisibility(this, nsViewVisibility_kHide);    if (PR_TRUE == aRethink)    {      nsIScrollableView *par;      if (NS_OK == mParent->QueryInterface(NS_GET_IID(nsIScrollableView), (void **)&par)) {        par->ComputeScrollOffsets(PR_TRUE);      }    }  }}