fix notification in deleteChildren()

jsonform/gadget_json_generated_form_child.js

@@ -1759,19 +1759,25 @@
           }
         }
       }
-      element.parentNode.removeChild(element);
       for (key in g.props.add_custom_data) {
         if (g.props.add_custom_data.hasOwnProperty(key)) {
-          tasks.push(g.props.add_custom_data[key].rerender());
+          tasks.push(g.props.add_custom_data[key].rerender);
         }
       }
       for (i = 0; i < button_list.length; i = i + 1) {
-        tasks.push(button_list[i].rerender());
+        tasks.push(button_list[i].rerender);
       }
-      tasks.push(g.rootNotifyChange());
       return RSVP.Queue()
         .push(function () {
           return RSVP.all(tasks);
+        })
+        .push(function () {
+          return g.rootNotifyChange();
+        })
+        .push(function () {
+          // remove gadget at end otherwise
+          // current queue canceled.
+          element.parentNode.removeChild(element);
         });
     })