public function addColumn($columns)
    {
        unset($columns['date']);

        foreach ($this->data as $id => $field) {
            if (isset($field->show_admin_column) && $field->show_admin_column) {
                $columns[$id] = $field->label;
            }
        }

        $columns['date'] = __('Date');

        return $columns;
    }