Improve the instance-view page in observatory.

runtime/bin/vmservice/client/lib/src/elements/instance_ref.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library instance_ref_element;
 
 import 'package:polymer/polymer.dart';
 import 'package:observatory/service.dart';
 import 'service_ref.dart';
 
@@ skipping 20 matching lines @@
     return super.hoverText;
   }
 
   // TODO(turnidge): This is here to workaround vm/dart2js differences.
   dynamic expander() {
     return expandEvent;
   }
 
   void expandEvent(bool expand, var done) {
     assert(ref is ServiceMap);
-    ServiceMap refMap = ref;
     if (expand) {
-      refMap.reload().then((_) {
-        if (refMap['preview'] != null) {
-          refMap.name = refMap['preview'];
-          refMap.vmName = refMap['preview'];
+      ref.reload().then((result) {
+        if (result['preview'] != null) {
+          result.name = result['preview'];
+          result.vmName = result['preview'];
         }
+        ref = result;
+        notifyPropertyChange(#ref, 0, 1);
       }).whenComplete(done);
     } else {
+      ServiceMap refMap = ref;
       refMap['fields'] = null;
       refMap['elements'] = null;
       done();
     }
   }
 }