diff --git a/IPython/html/static/notebook/js/cell.js b/IPython/html/static/notebook/js/cell.js
index 05562a1..13bd925 100644
--- a/IPython/html/static/notebook/js/cell.js
+++ b/IPython/html/static/notebook/js/cell.js
@@ -38,23 +38,24 @@ define([
      * @param {object|undefined} [options]
      *     @param [options.cm_config] {object} config to pass to CodeMirror, will extend default parameters
      */
-    var Cell = function (options, keyboard_manager, events) {
-        this.keyboard_manager = keyboard_manager;
-        this.events = events;
-        options = this.mergeopt(Cell, options);
+    var Cell = function (options) {
+        options = options || {};
+        this.keyboard_manager = options.keyboard_manager;
+        this.events = options.events;
+        var config = this.mergeopt(Cell, options.config);
         // superclass default overwrite our default
         
-        this.placeholder = options.placeholder || '';
-        this.read_only = options.cm_config.readOnly;
+        this.placeholder = config.placeholder || '';
+        this.read_only = config.cm_config.readOnly;
         this.selected = false;
         this.rendered = false;
         this.mode = 'command';
         this.metadata = {};
         // load this from metadata later ?
         this.user_highlight = 'auto';
-        this.cm_config = options.cm_config;
+        this.cm_config = config.cm_config;
         this.cell_id = utils.uuid();
-        this._options = options;
+        this._options = config;
 
         // For JS VM engines optimization, attributes should be all set (even
         // to null) in the constructor, and if possible, if different subclass
diff --git a/IPython/html/static/notebook/js/codecell.js b/IPython/html/static/notebook/js/codecell.js
index b5a63ef..3869d7a 100644
--- a/IPython/html/static/notebook/js/codecell.js
+++ b/IPython/html/static/notebook/js/codecell.js
@@ -54,13 +54,14 @@ define([
      * @param {object|undefined} [options]
      *      @param [options.cm_config] {object} config to pass to CodeMirror
      */
-    var CodeCell = function (kernel, options, events, config, keyboard_manager, notebook) {
+    var CodeCell = function (kernel, options) {
+        options = options || {};
         this.kernel = kernel || null;
-        this.notebook = notebook;
+        this.notebook = options.notebook;
         this.collapsed = false;
-        this.tooltip = new tooltip.Tooltip(events);
-        this.events = events;
-        this.config = config;
+        this.events = options.events;
+        this.tooltip = new tooltip.Tooltip(this.events);
+        this.config = options.config;
 
         // create all attributed in constructor function
         // even if null for V8 VM optimisation
@@ -75,9 +76,11 @@ define([
             onKeyEvent: $.proxy(this.handle_keyevent,this)
         };
 
-        options = this.mergeopt(CodeCell, options, {cm_config:cm_overwrite_options});
-
-        Cell.apply(this,[options, keyboard_manager, events]);
+        var config = this.mergeopt(CodeCell, this.config, {cm_config: cm_overwrite_options});
+        Cell.apply(this,[{
+            config: config, 
+            keyboard_manager: options.keyboard_manager, 
+            events: this.events}]);
 
         // Attributes we want to override in this subclass.
         this.cell_type = "code";
diff --git a/IPython/html/static/notebook/js/keyboardmanager.js b/IPython/html/static/notebook/js/keyboardmanager.js
index 519a41f..dad667d 100644
--- a/IPython/html/static/notebook/js/keyboardmanager.js
+++ b/IPython/html/static/notebook/js/keyboardmanager.js
@@ -15,17 +15,17 @@ define([
     // Main keyboard manager for the notebook
     var keycodes = keyboard.keycodes;
 
-    var KeyboardManager = function (pager, events) {
+    var KeyboardManager = function (options) {
         this.mode = 'command';
         this.enabled = true;
-        this.pager = pager;
+        this.pager = options.pager;
         this.quick_help = undefined;
         this.notebook = undefined;
         this.bind_events();
-        this.command_shortcuts = new keyboard.ShortcutManager(undefined, events);
+        this.command_shortcuts = new keyboard.ShortcutManager(undefined, options.events);
         this.command_shortcuts.add_shortcuts(this.get_default_common_shortcuts());
         this.command_shortcuts.add_shortcuts(this.get_default_command_shortcuts());
-        this.edit_shortcuts = new keyboard.ShortcutManager(undefined, events);
+        this.edit_shortcuts = new keyboard.ShortcutManager(undefined, options.events);
         this.edit_shortcuts.add_shortcuts(this.get_default_common_shortcuts());
         this.edit_shortcuts.add_shortcuts(this.get_default_edit_shortcuts());
     };
diff --git a/IPython/html/static/notebook/js/main.js b/IPython/html/static/notebook/js/main.js
index 53e1d93..6f7a2b8 100644
--- a/IPython/html/static/notebook/js/main.js
+++ b/IPython/html/static/notebook/js/main.js
@@ -42,7 +42,7 @@ require([
     $('#ipython-main-app').addClass('border-box-sizing');
     $('div#notebook_panel').addClass('border-box-sizing');
 
-    var options = {
+    var common_options = {
         base_url : utils.get_body_data("baseUrl"),
         notebook_path : utils.get_body_data("notebookPath"),
         notebook_name : utils.get_body_data('notebookName')
@@ -52,15 +52,38 @@ require([
     var page = new page.Page();
     var layout_manager = new layoutmanager.LayoutManager();
     var events = $([new events.Events()]);
-    var pager = new pager.Pager('div#pager', 'div#pager_splitter', layout_manager, events);
-    var keyboard_manager = new keyboardmanager.KeyboardManager(pager, events);
+    var pager = new pager.Pager('div#pager', 'div#pager_splitter', {
+        layout_manager: layout_manager, 
+        events: events});
+    var keyboard_manager = new keyboardmanager.KeyboardManager({
+        pager: pager, 
+        events: events});
     var save_widget = new savewidget.SaveWidget('span#save_widget', events);
-    var notebook = new notebook.Notebook('div#notebook', options, events, keyboard_manager, save_widget, user_config);
-    var login_widget = new loginwidget.LoginWidget('span#login_widget', options);
-    var toolbar = new maintoolbar.MainToolBar('#maintoolbar-container', layout_manager, notebook, events);
-    var quick_help = new quickhelp.QuickHelp(undefined, keyboard_manager, events);
-    var menubar = new menubar.MenuBar('#menubar', options, notebook, layout_manager, events, save_widget, quick_help);
-    var notification_area = new notificationarea.NotificationArea('#notification_area', events, save_widget, notebook);
+    var notebook = new notebook.Notebook('div#notebook', $.extend({
+        events: events,
+        keyboard_manager: keyboard_manager,
+        save_widget: save_widget,
+        config: user_config},
+        common_options));
+    var login_widget = new loginwidget.LoginWidget('span#login_widget', common_options);
+    var toolbar = new maintoolbar.MainToolBar('#maintoolbar-container', {
+        notebook: notebook, 
+        events: events}); 
+    var quick_help = new quickhelp.QuickHelp({
+        keyboard_manager: keyboard_manager, 
+        events: events});
+    var menubar = new menubar.MenuBar('#menubar', $.extend({
+        notebook: notebook, 
+        layout_manager: layout_manager, 
+        events: events, 
+        save_widget: save_widget, 
+        quick_help: quick_help}, 
+        common_options));
+    var notification_area = new notificationarea.NotificationArea(
+        '#notification_area', {
+        events: events, 
+        save_widget: save_widget, 
+        notebook: notebook});
     notification_area.init_notification_widgets();
 
     $('body').append('<div id="fonttest"><pre><span id="test1">x</span>'+
@@ -91,7 +114,7 @@ require([
     
     events.on('notebook_loaded.Notebook', first_load);
     events.trigger('app_initialized.NotebookApp');
-    notebook.load_notebook(options.notebook_name, options.notebook_path);
+    notebook.load_notebook(common_options.notebook_name, common_options.notebook_path);
 
     ipython.page = page;
     ipython.layout_manager = layout_manager;
diff --git a/IPython/html/static/notebook/js/maintoolbar.js b/IPython/html/static/notebook/js/maintoolbar.js
index f899f7d..e14e93f 100644
--- a/IPython/html/static/notebook/js/maintoolbar.js
+++ b/IPython/html/static/notebook/js/maintoolbar.js
@@ -9,10 +9,10 @@ define([
 ], function(IPython, $, toolbar, celltoolbar) {
     "use strict";
 
-    var MainToolBar = function (selector, layout_manager, notebook, events) {
+    var MainToolBar = function (selector, options) {
         toolbar.ToolBar.apply(this, arguments);
-        this.events = events;
-        this.notebook = notebook;
+        this.events = options.events;
+        this.notebook = options.notebook;
         this.construct();
         this.add_celltype_list();
         this.add_celltoolbar_list();
diff --git a/IPython/html/static/notebook/js/menubar.js b/IPython/html/static/notebook/js/menubar.js
index c0d79dd..9698d58 100644
--- a/IPython/html/static/notebook/js/menubar.js
+++ b/IPython/html/static/notebook/js/menubar.js
@@ -24,18 +24,18 @@ define([
      *      $('body').data('baseUrl');
      *      does not support change for now is set through this option
      */
-    var MenuBar = function (selector, options, notebook, layout_manager, events, save_widget, quick_help) {
+    var MenuBar = function (selector, options) {
         options = options || {};
         this.base_url = options.base_url || utils.get_body_data("baseUrl");
         this.selector = selector;
-        this.notebook = notebook;
-        this.layout_manager = layout_manager;
-        this.events = events;
-        this.save_widget = save_widget;
-        this.quick_help = quick_help;
+        this.notebook = options.notebook;
+        this.layout_manager = options.layout_manager;
+        this.events = options.events;
+        this.save_widget = options.save_widget;
+        this.quick_help = options.quick_help;
 
         try {
-            this.tour = new tour.Tour(notebook, events);
+            this.tour = new tour.Tour(this.notebook, this.events);
         } catch (e) {
             this.tour = undefined;
             console.log("Failed to instantiate Notebook Tour", e);
diff --git a/IPython/html/static/notebook/js/notebook.js b/IPython/html/static/notebook/js/notebook.js
index 0a190b3..6389862 100644
--- a/IPython/html/static/notebook/js/notebook.js
+++ b/IPython/html/static/notebook/js/notebook.js
@@ -38,15 +38,18 @@ define([
      * @param {Object} [options] A config object
      * @param {Object} [events] An events object
      */
-    var Notebook = function (selector, options, events, keyboard_manager, save_widget, config) {
-        this.config = config;
-        this.events = events;
-        this.keyboard_manager = keyboard_manager;
+    var Notebook = function (selector, options) {
+        this.config = options.config || {};
+        this.base_url = options.base_url;
+        this.notebook_path = options.notebook_path;
+        this.notebook_name = options.notebook_name;
+        this.events = options.events;
+        this.keyboard_manager = options.keyboard_manager;
+        this.save_widget = options.save_widget;
         // TODO: This code smells (and the other `= this` line a couple lines down)
         // We need a better way to deal with circular instance references.
-        keyboard_manager.notebook = this;
-        this.save_widget = save_widget;
-        save_widget.notebook = this;
+        this.keyboard_manager.notebook = this;
+        this.save_widget.notebook = this;
         
         mathjaxutils.init();
 
@@ -76,10 +79,6 @@ define([
         IPython.save_widget = this.save_widget;
         IPython.keyboard = this.keyboard;
 
-        this.options = options = options || {};
-        this.base_url = options.base_url;
-        this.notebook_path = options.notebook_path;
-        this.notebook_name = options.notebook_name;
         this.element = $(selector);
         this.element.scroll();
         this.element.data("notebook", this);
@@ -806,15 +805,24 @@ define([
         type = type || this.get_selected_cell().cell_type;
 
         if (ncells === 0 || this.is_valid_cell_index(index) || index === ncells) {
+            var cell_options = {
+                base_url: base_url,
+                notebook_path: notebook_path,
+                notebook_name: notebook_name,
+                events: this.events, 
+                config: this.config, 
+                keyboard_manager: this.keyboard_manager, 
+                notebook: this
+            };
             if (type === 'code') {
-                cell = new codecell.CodeCell(this.kernel, this.options, this.events, this.config, this.keyboard_manager, this);
+                cell = new codecell.CodeCell(this.kernel, cell_options);
                 cell.set_input_prompt();
             } else if (type === 'markdown') {
-                cell = new cells.MarkdownCell(this.options, this.events, this.config, this.keyboard_manager, this);
+                cell = new cells.MarkdownCell(cell_options);
             } else if (type === 'raw') {
-                cell = new cells.RawCell(this.options, this.events, this.config, this.keyboard_manager, this);
+                cell = new cells.RawCell(cell_options);
             } else if (type === 'heading') {
-                cell = new cells.HeadingCell(this.options, this.events, this.config, this.keyboard_manager, this);
+                cell = new cells.HeadingCell(cell_options);
             }
 
             if(this._insert_element_at_index(cell.element,index)) {
@@ -1465,7 +1473,11 @@ define([
      * @method start_session
      */
     Notebook.prototype.start_session = function () {
-        this.session = new session.Session(this, this.options);
+        this.session = new session.Session(this, {
+            base_url: base_url,
+            notebook_path: notebook_path,
+            notebook_name: notebook_name,
+            notebook: this});
         this.session.start($.proxy(this._session_started, this));
     };
 
diff --git a/IPython/html/static/notebook/js/notificationarea.js b/IPython/html/static/notebook/js/notificationarea.js
index 563615f..59d3a8c 100644
--- a/IPython/html/static/notebook/js/notificationarea.js
+++ b/IPython/html/static/notebook/js/notificationarea.js
@@ -10,11 +10,11 @@ define([
 ], function(IPython, $, utils, dialog, notificationwidget) {
     "use strict";
 
-    var NotificationArea = function (selector, events, save_widget, notebook) {
+    var NotificationArea = function (selector, options) {
         this.selector = selector;
-        this.events = events;
-        this.save_widget = save_widget;
-        this.notebook = notebook;
+        this.events = options.events;
+        this.save_widget = options.save_widget;
+        this.notebook = options.notebook;
         if (this.selector !== undefined) {
             this.element = $(selector);
         }
diff --git a/IPython/html/static/notebook/js/pager.js b/IPython/html/static/notebook/js/pager.js
index 034e2b3..744f339 100644
--- a/IPython/html/static/notebook/js/pager.js
+++ b/IPython/html/static/notebook/js/pager.js
@@ -8,13 +8,13 @@ define([
 ], function(IPython, $, utils) {
     "use strict";
 
-    var Pager = function (pager_selector, pager_splitter_selector, layout_manager, events) {
-        this.events = events;
+    var Pager = function (pager_selector, pager_splitter_selector, options) {
+        this.events = options.events;
         this.pager_element = $(pager_selector);
         this.pager_button_area = $('#pager_button_area');
         var that = this;
         this.percentage_height = 0.40;
-        layout_manager.pager = this;
+        options.layout_manager.pager = this;
         this.pager_splitter_element = $(pager_splitter_selector)
             .draggable({
                         containment: 'window',
@@ -23,7 +23,7 @@ define([
                         drag: function(event, ui) {
                             // recalculate the amount of space the pager should take
                             var pheight = ($(document.body).height()-event.clientY-4);
-                            var downprct = pheight/layout_manager.app_height();
+                            var downprct = pheight/options.layout_manager.app_height();
                                 downprct = Math.min(0.9, downprct);
                             if (downprct < 0.1) {
                                 that.percentage_height = 0.1;
@@ -32,7 +32,7 @@ define([
                                 that.percentage_height = downprct;
                                 that.expand({'duration':0});
                             }
-                            layout_manager.do_resize();
+                            options.layout_manager.do_resize();
                        }
             });
         this.expanded = false;
diff --git a/IPython/html/static/notebook/js/quickhelp.js b/IPython/html/static/notebook/js/quickhelp.js
index 316208d..aecf961 100644
--- a/IPython/html/static/notebook/js/quickhelp.js
+++ b/IPython/html/static/notebook/js/quickhelp.js
@@ -10,10 +10,10 @@ define([
     "use strict";
     var platform = utils.platform;
 
-    var QuickHelp = function (selector, keyboard_manager, events) {
-        this.keyboard_manager = keyboard_manager;
-        keyboard_manager.quick_help = this;
-        this.events = events;
+    var QuickHelp = function (options) {
+        this.keyboard_manager = options.keyboard_manager;
+        this.keyboard_manager.quick_help = this;
+        this.events = options.events;
     };
 
     var cmd_ctrl = 'Ctrl-';
diff --git a/IPython/html/static/notebook/js/textcell.js b/IPython/html/static/notebook/js/textcell.js
index f1db79a..1eb3f57 100644
--- a/IPython/html/static/notebook/js/textcell.js
+++ b/IPython/html/static/notebook/js/textcell.js
@@ -24,27 +24,28 @@ define([
      *      @param [options.cm_config] {object} config to pass to CodeMirror, will extend/overwrite default config
      *      @param [options.placeholder] {string} default string to use when souce in empty for rendering (only use in some TextCell subclass)
      */
-    var TextCell = function (options, events, config, keyboard_manager, notebook) {
+    var TextCell = function (options) {
+        options = options || {};
         // in all TextCell/Cell subclasses
         // do not assign most of members here, just pass it down
         // in the options dict potentially overwriting what you wish.
         // they will be assigned in the base class.
-        this.notebook = notebook;
-        this.events = events;
-        this.config = config;
+        this.notebook = options.notebook;
+        this.events = options.events;
+        this.config = options.config;
         
         // we cannot put this as a class key as it has handle to "this".
         var cm_overwrite_options  = {
             onKeyEvent: $.proxy(this.handle_keyevent,this)
         };
-
-        options = this.mergeopt(TextCell,options,{cm_config:cm_overwrite_options});
+        var config = this.mergeopt(TextCell, this.config, {cm_config:cm_overwrite_options});
+        Cell.apply(this, [{
+                    config: config, 
+                    keyboard_manager: options.keyboard_manager, 
+                    events: events}]);
 
         this.cell_type = this.cell_type || 'text';
         mathjaxutils = mathjaxutils;
-
-        Cell.apply(this, [options, keyboard_manager, events]);
-
         this.rendered = false;
     };
 
@@ -218,11 +219,12 @@ define([
      * @constructor MarkdownCell
      * @extends IPython.HTMLCell
      */
-    var MarkdownCell = function (options, events, config, keyboard_manager) {
-        options = this.mergeopt(MarkdownCell, options);
+    var MarkdownCell = function (options) {
+        options = options || {};
+        var config = this.mergeopt(MarkdownCell, options.config);
+        TextCell.apply(this, [$.extend({}, options, {config: config})]);
 
         this.cell_type = 'markdown';
-        TextCell.apply(this, [options, events, config, keyboard_manager]);
     };
 
     MarkdownCell.options_default = {
@@ -268,13 +270,14 @@ define([
      * @constructor RawCell
      * @extends TextCell
      */
-    var RawCell = function (options, events, config, keyboard_manager) {
+    var RawCell = function (options) {
+        options = options || {};
+        var config = this.mergeopt(RawCell, options.config);
+        TextCell.apply(this, [$.extend({}, options, {config: config})]);
 
-        options = this.mergeopt(RawCell,options);
-        TextCell.apply(this, [options, events, config, keyboard_manager]);
-        this.cell_type = 'raw';
         // RawCell should always hide its rendered div
         this.element.find('div.text_cell_render').hide();
+        this.cell_type = 'raw';
     };
 
     RawCell.options_default = {
@@ -327,17 +330,13 @@ define([
      * @constructor HeadingCell
      * @extends TextCell
      */
-    var HeadingCell = function (options, events, config, keyboard_manager) {
-        options = this.mergeopt(HeadingCell, options);
+    var HeadingCell = function (options) {
+        options = options || {};
+        var config = this.mergeopt(HeadingCell, options.config);
+        TextCell.apply(this, [$.extend({}, options, {config: config})]);
 
         this.level = 1;
         this.cell_type = 'heading';
-        TextCell.apply(this, [options, events, config, keyboard_manager]);
-
-        /**
-         * heading level of the cell, use getter and setter to access
-         * @property level
-         */
     };
 
     HeadingCell.options_default = {
diff --git a/IPython/html/static/services/sessions/js/session.js b/IPython/html/static/services/sessions/js/session.js
index 6e791e0..9d53d00 100644
--- a/IPython/html/static/services/sessions/js/session.js
+++ b/IPython/html/static/services/sessions/js/session.js
@@ -9,10 +9,10 @@ define([
 ], function(IPython, $, utils, kernel) {
     "use strict";
 
-    var Session = function(notebook, options){
+    var Session = function(options){
         this.kernel = null;
         this.id = null;
-        this.notebook = notebook;
+        this.notebook = options.notebook;
         this.name = notebook.notebook_name;
         this.path = notebook.notebook_path;
         this.base_url = notebook.base_url;
diff --git a/IPython/html/static/tree/js/kernellist.js b/IPython/html/static/tree/js/kernellist.js
index b2e4e70..62305b7 100644
--- a/IPython/html/static/tree/js/kernellist.js
+++ b/IPython/html/static/tree/js/kernellist.js
@@ -8,8 +8,10 @@ define([
 ], function(IPython, $, notebooklist) {
     "use strict";
 
-    var KernelList = function (selector, options, session_list) {
-        notebooklist.NotebookList.call(this, selector, options, 'running', session_list);
+    var KernelList = function (selector, options) {
+        notebooklist.NotebookList.call(this, selector, $.extend({
+            element_name: 'running'}, 
+            options));
     };
 
     KernelList.prototype = Object.create(notebooklist.NotebookList.prototype);
diff --git a/IPython/html/static/tree/js/main.js b/IPython/html/static/tree/js/main.js
index c93bb1d..88ea1ff 100644
--- a/IPython/html/static/tree/js/main.js
+++ b/IPython/html/static/tree/js/main.js
@@ -1,7 +1,6 @@
 // Copyright (c) IPython Development Team.
 // Distributed under the terms of the Modified BSD License.
 
-var ipython = ipython || {};
 require([
     'base/js/namespace',
     'jquery',
@@ -29,16 +28,22 @@ require([
 
     page = new page.Page();
     
-    var opts = {
+    var common_options = {
         base_url: utils.get_body_data("baseUrl"),
         notebook_path: utils.get_body_data("notebookPath"),
     };
     events = $([new events.Events()]);
-    session_list = new sesssionlist.SesssionList(opts, events);
-    notebook_list = new notebooklist.NotebookList('#notebook_list', opts, undefined, session_list);
-    cluster_list = new clusterlist.ClusterList('#cluster_list', opts);
-    kernel_list = new kernellist.KernelList('#running_list', opts, session_list);
-    login_widget = new loginwidget.LoginWidget('#login_widget', opts);
+    session_list = new sesssionlist.SesssionList($.extend({
+        events: events}, 
+        common_options));
+    notebook_list = new notebooklist.NotebookList('#notebook_list', $.extend({
+        session_list:  session_list}, 
+        common_options));
+    cluster_list = new clusterlist.ClusterList('#cluster_list', common_options);
+    kernel_list = new kernellist.KernelList('#running_list',  $.extend({
+        session_list:  session_list}, 
+        common_options));
+    login_widget = new loginwidget.LoginWidget('#login_widget', common_options);
 
     $('#new_notebook').button().click(function (e) {
         notebook_list.new_notebook();
@@ -104,11 +109,11 @@ require([
     }
 
     // For backwards compatability.
-    ipython.page = page;
-    ipython.notebook_list = notebook_list;
-    ipython.cluster_list = cluster_list;
-    ipython.session_list = session_list;
-    ipython.kernel_list = kernel_list;
-    ipython.login_widget = login_widget;
-    ipython.events = events;
+    IPython.page = page;
+    IPython.notebook_list = notebook_list;
+    IPython.cluster_list = cluster_list;
+    IPython.session_list = session_list;
+    IPython.kernel_list = kernel_list;
+    IPython.login_widget = login_widget;
+    IPython.events = events;
 });
diff --git a/IPython/html/static/tree/js/notebooklist.js b/IPython/html/static/tree/js/notebooklist.js
index e5e3765..8fe2ba3 100644
--- a/IPython/html/static/tree/js/notebooklist.js
+++ b/IPython/html/static/tree/js/notebooklist.js
@@ -9,11 +9,11 @@ define([
 ], function(IPython, $, utils, dialog) {
     "use strict";
     
-    var NotebookList = function (selector, options, element_name, session_list) {
+    var NotebookList = function (selector, options) {
         var that = this;
-        this.session_list = session_list;
+        this.session_list = options.session_list;
         // allow code re-use by just changing element_name in kernellist.js
-        this.element_name = element_name || 'notebook';
+        this.element_name = options.element_name || 'notebook';
         this.selector = selector;
         if (this.selector !== undefined) {
             this.element = $(selector);
diff --git a/IPython/html/static/tree/js/sessionlist.js b/IPython/html/static/tree/js/sessionlist.js
index 93822d0..206b59e 100644
--- a/IPython/html/static/tree/js/sessionlist.js
+++ b/IPython/html/static/tree/js/sessionlist.js
@@ -9,7 +9,7 @@ define([
     "use strict";
 
     var SesssionList = function (options, events) {
-        this.events = events;
+        this.events = options.events;
         this.sessions = {};
         this.base_url = options.base_url || utils.get_body_data("baseUrl");
     };