comment model.set, so we know that it triggers update on other views

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

@@ -34,6 +34,9 @@ define(["notebook/js/widgets/widget"], function(widget_manager){
                 .attr('type', 'checkbox')
                 .click(function(el) {
                     that.user_invoked_update = true;
+            
+                    // Calling model.set will trigger all of the other views of the 
+                    // model to update.
                     that.model.set('value', that.$checkbox.prop('checked'));
                     that.touch();
                     that.user_invoked_update = false;
@@ -116,6 +119,9 @@ define(["notebook/js/widgets/widget"], function(widget_manager){
         // Handles and validates user input.
         handleClick: function(e) { 
             this.user_invoked_update = true;
+            
+            // Calling model.set will trigger all of the other views of the 
+            // model to update.
             this.model.set('value', ! $(e.target).hasClass('active'));
             this.touch();
             this.user_invoked_update = false;

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

@@ -96,6 +96,9 @@ define(["notebook/js/widgets/widget"], function(widget_manager){
                 .attr('data-parent', '#' + this.$el.attr('id'))
                 .attr('href', '#' + uuid)
                 .click(function(evt){ 
+            
+                    // Calling model.set will trigger all of the other views of the 
+                    // model to update.
                     that.model.set("selected_index", index);
                     that.touch();
                  })
@@ -194,6 +197,9 @@ define(["notebook/js/widgets/widget"], function(widget_manager){
                 .html('Page ' + index)
                 .appendTo(tab)
                 .click(function (e) {
+            
+                    // Calling model.set will trigger all of the other views of the 
+                    // model to update.
                     that.model.set("selected_index", index);
                     that.touch();
                     that.select_page(index);

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

@@ -104,6 +104,9 @@ define(["notebook/js/widgets/widget"], function(widget_manager){
 
         // Handle when a value is clicked.
         handle_click: function (e) {
+            
+            // Calling model.set will trigger all of the other views of the 
+            // model to update.
             this.model.set('value', $(e.target).html(), this);
             this.touch();
         },
@@ -193,6 +196,9 @@ define(["notebook/js/widgets/widget"], function(widget_manager){
 
         // Handle when a value is clicked.
         handle_click: function (e) {
+            
+            // Calling model.set will trigger all of the other views of the 
+            // model to update.
             this.model.set('value', $(e.target).val(), this);
             this.touch();
         },
@@ -277,6 +283,9 @@ define(["notebook/js/widgets/widget"], function(widget_manager){
 
         // Handle when a value is clicked.
         handle_click: function (e) {
+            
+            // Calling model.set will trigger all of the other views of the 
+            // model to update.
             this.model.set('value', $(e.target).html(), this);
             this.touch();
         },
@@ -358,6 +367,9 @@ define(["notebook/js/widgets/widget"], function(widget_manager){
 
         // Handle when a value is clicked.
         handle_click: function (e) {
+            
+            // Calling model.set will trigger all of the other views of the 
+            // model to update.
             this.model.set('value', $(e.target).html(), this);
             this.touch();
         },

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

@@ -124,6 +124,9 @@ define(["notebook/js/widgets/widget"], function(widget_manager){
         // Handles and validates user input.
         handleChanging: function(e) { 
             this.user_invoked_update = true;
+            
+            // Calling model.set will trigger all of the other views of the 
+            // model to update.
             this.model.set('value', e.target.value);
             this.touch();
             this.user_invoked_update = false;
@@ -180,6 +183,9 @@ define(["notebook/js/widgets/widget"], function(widget_manager){
         
         // Handles and validates user input.
         handleChanging: function(e) { 
+            
+            // Calling model.set will trigger all of the other views of the 
+            // model to update.
             this.model.set('value', e.target.value);
             this.touch();
         },