Don't refer to global kernelselector object in Session

IPython/html/static/notebook/js/kernelselector.js

@@ -12,6 +12,7 b' define(['
         this.selector = selector;
         this.notebook = notebook;
         this.events = notebook.events;
+        this.current_selection = notebook.default_kernel_name;
         this.kernelspecs = {};
         if (this.selector !== undefined) {
             this.element = $(selector);
@@ -42,7 +43,7 b' define(['
     };
 
     KernelSelector.prototype.change_kernel = function(kernel_name) {
-        if (kernel_name === this.notebook.kernel.name) {
+        if (kernel_name === this.current_selection) {
             return;
         }
         var ks = this.kernelspecs[kernel_name];
@@ -54,8 +55,19 b' define(['
     KernelSelector.prototype.bind_events = function() {
         var that = this;
         this.events.on('spec_changed.Kernel', function(event, data) {
+            that.current_selection = data.name;
             that.element.find("#current_kernel_spec").find('.kernel_name').text(data.display_name);
         });
+        
+        this.events.on('started.Session', function(events, session) {
+            if (session.kernel_name !== that.current_selection) {
+                // If we created a 'python' session, we only know if it's Python
+                // 3 or 2 on the server's reply, so we fire the event again to
+                // set things up.
+                var ks = that.kernelspecs[session.kernel_name];
+                that.events.trigger('spec_changed.Kernel', ks);
+            }
+        });
     };
 
     return {'KernelSelector': KernelSelector};

IPython/html/static/services/sessions/js/session.js

@@ -13,6 +13,7 b' define(['
         this.kernel = null;
         this.id = null;
         this.notebook = options.notebook;
+        this.events = options.notebook.events;
         this.name = options.notebook_name;
         this.path = options.notebook_path;
         this.kernel_name = options.kernel_name;
@@ -92,13 +93,8 b' define(['
     Session.prototype._handle_start_success = function (data, status, xhr) {
         this.id = data.id;
         // If we asked for 'python', the response will have 'python3' or 'python2'.
-        // In this case, fire the spec changed event again to update the name
-        // and highlighting.
-        if (data.kernel.name !== this.kernel_name) {
-            this.kernel_name = data.kernel.name;
-            var ks = IPython.kernelselector.kernelspecs[this.kernel_name];
-            this.notebook.events.trigger('spec_changed.Kernel', ks);
-        }
+        this.kernel_name = data.kernel.name;
+        this.events.trigger('started.Session', this);
         var kernel_service_url = utils.url_path_join(this.base_url, "api/kernels");
         this.kernel = new kernel.Kernel(kernel_service_url, this.ws_url, this.notebook, this.kernel_name);
         this.kernel._kernel_started(data.kernel);