diff --git a/notebook/static/notebook/js/cell.js b/notebook/static/notebook/js/cell.js
index 9b6379a687..eceda62a10 100644
--- a/notebook/static/notebook/js/cell.js
+++ b/notebook/static/notebook/js/cell.js
@@ -49,10 +49,9 @@ define([
         options = options || {};
         this.keyboard_manager = options.keyboard_manager;
         this.events = options.events;
-        var config = utils.mergeopt(Cell, options.config);
+        var config = options.config;
         // superclass default overwrite our default
         
-        this.placeholder = config.placeholder || '';
         this.selected = false;
         this.anchor = false;
         this.rendered = false;
@@ -83,19 +82,21 @@ define([
         // load this from metadata later ?
         this.user_highlight = 'auto';
 
-
-        var _local_cm_config = {};
-        if(this.class_config){
-            _local_cm_config = this.class_config.get_sync('cm_config');
+        // merge my class-specific config data with general cell-level config
+        var class_config_data = {};
+        if (this.class_config) {
+            class_config_data = this.class_config.get_sync();
         }
-        
-        var local = new configmod.ConfigWithDefaults(options.config,
-            {}, 'Cell');
-        var llcm = local.get_sync('cm_config');
 
-        config.cm_config = utils.mergeopt({}, config.cm_config, utils.mergeopt({}, llcm, _local_cm_config));
+        var cell_config = new configmod.ConfigWithDefaults(options.config,
+            Cell.options_default, 'Cell');
+        var cell_config_data = cell_config.get_sync();
+
+        // this._options is a merge of SomeCell and Cell config data:
+        this._options = utils.mergeopt({}, cell_config_data, class_config_data);
+        this.placeholder = this._options.placeholder || '';
+
         this.cell_id = utils.uuid();
-        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/notebook/static/notebook/js/codecell.js b/notebook/static/notebook/js/codecell.js
index ef69791c1c..11e6a087e2 100644
--- a/notebook/static/notebook/js/codecell.js
+++ b/notebook/static/notebook/js/codecell.js
@@ -96,7 +96,7 @@ define([
         this.tooltip = options.tooltip;
         this.config = options.config;
         this.class_config = new configmod.ConfigWithDefaults(this.config,
-                                        CodeCell.config_defaults, 'CodeCell');
+                                        CodeCell.options_default, 'CodeCell');
 
         // create all attributed in constructor function
         // even if null for V8 VM optimisation
@@ -141,8 +141,6 @@ define([
         },
     };
 
-    CodeCell.config_defaults = CodeCell.options_default;
-
     CodeCell.msg_cells = {};
 
     CodeCell.prototype = Object.create(Cell.prototype);
diff --git a/notebook/static/notebook/js/codemirror-ipythongfm.js b/notebook/static/notebook/js/codemirror-ipythongfm.js
index 293d17dca7..f840964e2f 100644
--- a/notebook/static/notebook/js/codemirror-ipythongfm.js
+++ b/notebook/static/notebook/js/codemirror-ipythongfm.js
@@ -55,5 +55,16 @@
         }, 'gfm');
 
         CodeMirror.defineMIME("text/x-ipythongfm", "ipythongfm");
+
+        // async workaround:
+        // Cells may be loaded before this mode is defined.
+        // If that happens, trigger re-load of the mode:
+        if (Jupyter && Jupyter.notebook) {
+            Jupyter.notebook.get_cells().map(function (cell) {
+                if (cell.code_mirror && cell.code_mirror.getOption('mode') === 'ipythongfm') {
+                    cell.code_mirror.setOption('mode', 'ipythongfm');
+                }
+            });
+        }
     });
-})
+});
diff --git a/notebook/static/notebook/js/textcell.js b/notebook/static/notebook/js/textcell.js
index 9ba54b4aed..fdb7e48ceb 100644
--- a/notebook/static/notebook/js/textcell.js
+++ b/notebook/static/notebook/js/textcell.js
@@ -56,7 +56,6 @@ define([
         this.notebook = options.notebook;
         
         // we cannot put this as a class key as it has handle to "this".
-        var config = utils.mergeopt(TextCell, this.config);
         Cell.apply(this, [{
                     config: options.config, 
                     keyboard_manager: options.keyboard_manager, 
@@ -279,9 +278,9 @@ define([
          *          notebook: Notebook instance
          */
         options = options || {};
-        var config = utils.mergeopt(MarkdownCell, {});
+        var config_default = utils.mergeopt(TextCell, MarkdownCell.options_default);
         this.class_config = new configmod.ConfigWithDefaults(options.config,
-                                            {}, 'MarkdownCell');
+                                            config_default, 'MarkdownCell');
         TextCell.apply(this, [$.extend({}, options, {config: options.config})]);
 
         this.cell_type = 'markdown';
@@ -527,24 +526,20 @@ define([
          *          notebook: Notebook instance
          */
         options = options || {};
-        var config = utils.mergeopt(RawCell, {});
-        TextCell.apply(this, [$.extend({}, options, {config: options.config})]);
-
+        var config_default = utils.mergeopt(TextCell, RawCell.options_default);
         this.class_config = new configmod.ConfigWithDefaults(options.config,
-                                            RawCell.config_defaults, 'RawCell');
+                                            config_default, 'RawCell');
+        TextCell.apply(this, [$.extend({}, options, {config: options.config})]);
         this.cell_type = 'raw';
     };
 
     RawCell.options_default = {
-        placeholder : "Write raw LaTeX or other formats here, for use with nbconvert. " +
-            "It will not be rendered in the notebook. " + 
-            "When passing through nbconvert, a Raw Cell's content is added to the output unmodified."
-    };
-    
-    RawCell.config_defaults =  {
         highlight_modes : {
             'diff'         :{'reg':[/^diff/]}
         },
+        placeholder : "Write raw LaTeX or other formats here, for use with nbconvert. " +
+            "It will not be rendered in the notebook. " +
+            "When passing through nbconvert, a Raw Cell's content is added to the output unmodified.",
     };
 
     RawCell.prototype = Object.create(TextCell.prototype);
diff --git a/notebook/static/services/config.js b/notebook/static/services/config.js
index 9c5d7dda8e..822306d9f6 100644
--- a/notebook/static/services/config.js
+++ b/notebook/static/services/config.js
@@ -102,7 +102,21 @@ function(utils) {
      */
     ConfigWithDefaults.prototype.get_sync = function(key) {
         var data = this._class_data();
-        return key in data ? data[key] : this.defaults[key];
+        if (key === undefined) {
+            // no key specified, return full config data
+            return $.extend(true, {}, this.defaults, data);
+        }
+
+        var value = data[key];
+        if (value !== undefined) {
+            if (typeof value == 'object') {
+                // merge with defaults if it's an object
+                return $.extend(true, {}, this.defaults[key], value);
+            } else {
+                return value;
+            }
+        }
+        return this.defaults[key];
     };
     
     /**
diff --git a/notebook/tests/notebook/dualmode_cellmode.js b/notebook/tests/notebook/dualmode_cellmode.js
index 3701792d30..459d18a743 100644
--- a/notebook/tests/notebook/dualmode_cellmode.js
+++ b/notebook/tests/notebook/dualmode_cellmode.js
@@ -2,17 +2,26 @@
 
 // Test
 casper.notebook_test(function () {
+    function get_cell_cm_mode(index) {
+        return casper.evaluate(function (index) {
+            return Jupyter.notebook.get_cell(index).code_mirror.getMode().name;
+        }, {index: index});
+    }
+
     this.then(function () {
         // Cell mode change
+        var that = this;
         var index = 0;
         this.select_cell(index);
         var a = 'hello\nmulti\nline';
         this.set_cell_text(index, a);
         this.trigger_keydown('esc','r');
         this.test.assertEquals(this.get_cell(index).cell_type, 'raw', 'r; cell is raw');
+        this.test.assertEquals(get_cell_cm_mode(index), 'null', 'raw cell codemirror mode is null');
         this.trigger_keydown('1');
         this.test.assertEquals(this.get_cell(index).cell_type, 'markdown', '1; cell is markdown');
         this.test.assertEquals(this.get_cell_text(index), '# ' + a, '1; markdown heading');
+        this.test.assertEquals(get_cell_cm_mode(index), 'ipythongfm', 'codemirror cell mode is ipythongfm');
         this.trigger_keydown('2');
         this.test.assertEquals(this.get_cell(index).cell_type, 'markdown', '2; cell is markdown');
         this.test.assertEquals(this.get_cell_text(index), '## ' + a, '2; markdown heading');
@@ -34,6 +43,7 @@ casper.notebook_test(function () {
         this.trigger_keydown('y');
         this.test.assertEquals(this.get_cell(index).cell_type, 'code', 'y; cell is code');
         this.test.assertEquals(this.get_cell_text(index), '###### ' + a, 'y; still has hashes');
+        this.test.assertEquals(get_cell_cm_mode(index), 'ipython', 'code cell mode is ipython');
         this.trigger_keydown('1');
         this.test.assertEquals(this.get_cell(index).cell_type, 'markdown', '1; cell is markdown');
         this.test.assertEquals(this.get_cell_text(index), '# ' + a, '1; markdown heading');