framework/grid/CheckboxColumn.php
protected function getHeaderCheckBoxName()
    {
        $name = $this->name;
        if (substr_compare($name, '[]', -2, 2) === 0) {
            $name = substr($name, 0, -2);
        }
        if (substr_compare($name, ']', -1, 1) === 0) {
            $name = substr($name, 0, -1) . '_all]';
        } else {
            $name .= '_all';
        }

        return $name;
    }
protected function getHeaderCheckBoxName()
    {
        $name = $this->name;
        if (substr_compare($name, '[]', -2, 2) === 0) {
            $name = substr($name, 0, -2);
        }
        if (substr_compare($name, ']', -1, 1) === 0) {
            $name = substr($name, 0, -1) . '_all]';
        } else {
            $name .= '_all';
        }

        return $name;
    }
Returns header checkbox name.
@return string header checkbox name
@since 2.0.8