Render all items in this field together.
When using advanced render, each possible item in the list is rendered individually. Then the items are all pasted together.
protected function renderItems($items) {
if (!empty($items)) {
if ($this->options['type'] == 'separator') {
return implode($this
->sanitizeValue($this->options['separator'], 'xss_admin'), $items);
}
else {
$item_list = array(
'#theme' => 'item_list',
'#items' => $items,
'#title' => NULL,
'#type' => $this->options['type'],
);
return drupal_render($item_list);
}
}
}