public function render(array &$a_html, $a_parent_gui)
 {
     include_once "./Services/Taxonomy/classes/class.ilTaxonomyExplorerGUI.php";
     foreach (self::$valid_tax_map[$this->parent_ref_id] as $tax_id) {
         $tax_exp = new ilTaxonomyExplorerGUI($a_parent_gui, null, $tax_id, null, null);
         $tax_exp->setSkipRootNode(true);
         $tax_exp->setOnClick("il.Classification.toggle({tax_node: '{NODE_CHILD}'});");
         if (is_array($this->selection)) {
             foreach ($this->selection as $node_id) {
                 $tax_exp->setPathOpen($node_id);
                 $tax_exp->setNodeSelected($node_id);
             }
         }
         if (!$tax_exp->handleCommand()) {
             $a_html[] = array("title" => ilObject::_lookupTitle($tax_id), "html" => $tax_exp->getHTML());
         }
     }
 }