public function onRowHeightGet(TcTable $table, $row = null, $rowIndex = null) {
        // if current row index is one of the already-calculated widows height,
        // we take this value, instead of calculating it a second time.
        if ($rowIndex !== null && isset($this->_widowsCalculatedHeight[$rowIndex])) {
            return $this->_widowsCalculatedHeight[$rowIndex];
        }
    }