Add more improvements from the review.

cms/static/js/views/xblock_container.js

@@ -75,7 +75,10 @@ define(["jquery", "underscore", "js/views/baseview", "js/views/xblock", "js/view
             refreshXBlock: function(xblockInfo, xblockElement) {
                 var self = this,
                     temporaryView;
-                // Create a temporary view to render the updated XBlock into
+                // There is only one Backbone view created on the container page, which is
+                // for the container xblock itself. Any child xblocks rendered inside the
+                // container do not get a Backbone view. Thus, create a temporary XBlock
+                // around the child element so that it can be refreshed.
                 temporaryView = new XBlockView({
                     el: xblockElement,
                     model: xblockInfo,

cms/static/js/views/xblock_editor.js

@@ -106,14 +106,11 @@ define(["jquery", "underscore", "gettext", "js/views/feedback_notification", "js
             getXBlockData: function() {
                 var xblock = this.xblock,
                     metadataEditor = this.getMetadataEditor(),
-                    metadata,
                     data;
                 data = xblock.save();
-                metadata = data.metadata;
                 if (metadataEditor) {
-                    metadata = _.extend(metadata || {}, this.getChangedMetadata());
+                    data.metadata = _.extend(data.metadata || {}, this.getChangedMetadata());
                 }
-                data.metadata = metadata;
                 return data;
             },