TREEJS Fix ids function

SE/superedit-TREEJS.php

@@ -594,7 +594,7 @@ function <?php echo $htmlTreeId; ?>_setIds(btnNode, id, idsList) {
 	var idsList = idsList || [];
 
 	var ddNode = btnNode.parentNode.nextSibling;
-	if (!ddNode) {
+	if (!ddNode || ddNode.nodeType != 1) {
 		ddNode = document.createElement('dd');
 		btnNode.parentNode.parentNode.insertBefore(ddNode, btnNode.parentNode.nextSibling);
 	}