diff --git a/navalplanner-webapp/src/main/webapp/orders/_orderElementTree.zul b/navalplanner-webapp/src/main/webapp/orders/_orderElementTree.zul
index 980cb2e61..9aab5a25d 100644
--- a/navalplanner-webapp/src/main/webapp/orders/_orderElementTree.zul
+++ b/navalplanner-webapp/src/main/webapp/orders/_orderElementTree.zul
@@ -1,3 +1,4 @@
+<vbox id="orderElementTree">
     <vbox>
         <hbox>
             <button label="New order element"