Added ability to title multicontainer pages before multicontainer display()

IPython/html/static/notebook/js/widgets/multicontainer.js

@@ -14,10 +14,14 require(["notebook/js/widget"], function(){
             // Set tab titles
             var titles = this.model.get('_titles');
             for (var page_index in titles) {
-                var accordian_toggle = this.containers[page_index]
+
+                var accordian = this.containers[page_index]
+                if (accordian != undefined) {
+                    accordian
                     .find('.accordion-heading')
-                    .find('.accordion-toggle');
-                accordian_toggle.html(titles[page_index]);
+                        .find('.accordion-toggle')
+                        .html(titles[page_index]);
+                }
             }
 
             return IPython.WidgetView.prototype.update.call(this);
@@ -49,6 +53,7 require(["notebook/js/widget"], function(){
             this.containers.push(accordion_group);
 
             accordion_inner.append(view.$el);
+            this.update();
         },
     });
 

IPython/html/widgets/widget.py

@@ -160,6 +160,7 class Widget(LoggingConfigurable):
         key : unicode (optional)
             A single property's name to sync with the frontend.
         """
+        if self.comm is not None:
         state = {}
 
         # If a key is provided, just send the state of that key.