Craft\Formerly_SubmissionElementType::getTableAttributeHtml PHP Method

    public function getTableAttributeHtml(BaseElementModel $element, $attribute)
    {
        $value = $element->{$attribute};
        if ($value instanceof MultiOptionsFieldData) {
            $options = $value->getOptions();
            $summary = array();
            for ($j = 0; $j < count($options); ++$j) {
                $option = $options[$j];
                if ($option->selected) {
                    $summary[] = $option->label;
                }
            }
            return implode($summary, ', ');
        } else {
            return parent::getTableAttributeHtml($element, $attribute);
        }
    }