NS_METHOD nsWidget::Scroll( PRInt32 aDx, PRInt32 aDy, nsRect *aClipRect ) { return NS_OK; }
NS_IMETHOD Scroll(PRInt32 aDx, PRInt32 aDy, nsRect *aClipRect) { return NS_ERROR_FAILURE; }
NS_METHOD nsWidget::Scroll( PRInt32 aDx, PRInt32 aDy, nsRect *aClipRect ) {  return NS_OK;	}