insert additionalProperty before selector

gadget_json_generated_form.js

@@ -398,7 +398,8 @@
 
       function element_append(child) {
         if (child) {
-          div_input.appendChild(child);
+          // insert additionalProperty before selector
+          selector.element.parentNode.insertBefore(child, selector.element);
         }
       }
 
@@ -486,7 +487,10 @@
         return g.declareGadget("gadget_html5_select.html", {scope: scope});
       })
       .push(selector.rerender)
-      .push(root_append);
+      .push(function (element) {
+        selector.element = element;
+        return root_append(element);
+      });
 
     if (json_field.patternProperties !== undefined) {
       if (json_field.patternProperties['.*'] !== undefined) {