diff --git a/IPython/html/static/widgets/js/widget.js b/IPython/html/static/widgets/js/widget.js
index ae80f9e..66a88d1 100644
--- a/IPython/html/static/widgets/js/widget.js
+++ b/IPython/html/static/widgets/js/widget.js
@@ -413,7 +413,7 @@ define(["widgets/js/manager",
             this.model.on('change:_css', this.update_css, this);
 
             this.model.on('change:_dom_classes', function(model, new_classes) {
-                var old_classes = model.previous('children');
+                var old_classes = model.previous('_dom_classes');
                 this.update_classes(old_classes, new_classes);
             }, this);
 
diff --git a/IPython/html/tests/widgets/widget_box.js b/IPython/html/tests/widgets/widget_box.js
index c92402c..6e1f242 100644
--- a/IPython/html/tests/widgets/widget_box.js
+++ b/IPython/html/tests/widgets/widget_box.js
@@ -36,16 +36,16 @@ casper.notebook_test(function () {
     });
 
     index = this.append_cell(
-        'container.set_css("float", "right")\n'+
+        'container.box_style = "success"\n'+
         'print("Success")\n');
     this.execute_cell_then(index, function(index){
 
         this.test.assertEquals(this.get_output_cell(index).text, 'Success\n', 
-            'Set container class CSS cell executed with correct output.');
-        
-        this.test.assert(this.cell_element_function(container_index, 
-            '.widget-area .widget-subarea .my-test-class', 'css', ['float'])=='right',
-            'set_css works.');
+            'Set box_style cell executed with correct output.');
+
+        this.test.assert(this.cell_element_exists(container_index, 
+            '.widget-box.alert-success'),
+            'Set box_style works.');
     });
 
     index = this.append_cell(
diff --git a/IPython/html/tests/widgets/widget_float.js b/IPython/html/tests/widgets/widget_float.js
index 24294b4..291efb3 100644
--- a/IPython/html/tests/widgets/widget_float.js
+++ b/IPython/html/tests/widgets/widget_float.js
@@ -7,7 +7,7 @@ casper.notebook_test(function () {
     this.execute_cell_then(index);
 
     var float_text = {};
-    float_text.query = '.widget-area .widget-subarea .widget-hbox-single .my-second-float-text input';
+    float_text.query = '.widget-area .widget-subarea .my-second-float-text input';
     float_text.index = this.append_cell(
         'float_widget = widgets.FloatText()\n' +
         'display(float_widget)\n' + 
@@ -55,9 +55,9 @@ casper.notebook_test(function () {
             'Invald float textbox value caught and filtered.');
     });
 
-    var float_text_query = '.widget-area .widget-subarea .widget-hbox-single .widget-numeric-text';
+    var float_text_query = '.widget-area .widget-subarea .widget-numeric-text';
     var slider = {};
-    slider.query = '.widget-area .widget-subarea .widget-hbox-single .slider';
+    slider.query = '.widget-area .widget-subarea .slider';
     slider.index = this.append_cell(
         'floatrange = [widgets.BoundedFloatText(), \n' +
         '    widgets.FloatSlider()]\n' +
diff --git a/IPython/html/tests/widgets/widget_image.js b/IPython/html/tests/widgets/widget_image.js
index 2cce2d0..ba10d35 100644
--- a/IPython/html/tests/widgets/widget_image.js
+++ b/IPython/html/tests/widgets/widget_image.js
@@ -23,9 +23,6 @@ casper.notebook_test(function () {
         'image.value = data\n' +
         'image.width = "50px"\n' +
         'image.height = "50px"\n' +
-        // Set css that will make the image render within the PhantomJS visible
-        // window.  If we don't do this, the captured image will be black.
-        'image.set_css({"background": "blue", "z-index": "9999", "position": "fixed", "top": "0px", "left": "0px"})\n' + 
         'display(image)\n' + 
         'print("Success")\n');
     this.execute_cell_then(image_index, function(index){
diff --git a/IPython/html/tests/widgets/widget_int.js b/IPython/html/tests/widgets/widget_int.js
index a3a0263..409dfb6 100644
--- a/IPython/html/tests/widgets/widget_int.js
+++ b/IPython/html/tests/widgets/widget_int.js
@@ -7,7 +7,7 @@ casper.notebook_test(function () {
     this.execute_cell_then(index);
 
     var int_text = {};
-    int_text.query = '.widget-area .widget-subarea .widget-hbox-single .my-second-int-text input';
+    int_text.query = '.widget-area .widget-subarea .my-second-int-text input';
     int_text.index = this.append_cell(
         'int_widget = widgets.IntText()\n' +
         'display(int_widget)\n' + 
@@ -62,9 +62,9 @@ casper.notebook_test(function () {
     this.execute_cell_then(index);
 
 
-    var slider_query = '.widget-area .widget-subarea .widget-hbox-single .slider';
+    var slider_query = '.widget-area .widget-subarea .slider';
     var int_text2 = {};
-    int_text2.query = '.widget-area .widget-subarea .widget-hbox-single .my-second-num-test-text input';
+    int_text2.query = '.widget-area .widget-subarea .my-second-num-test-text input';
     int_text2.index = this.append_cell(
         'intrange = [widgets.BoundedIntTextWidget(),\n' +
         '    widgets.IntSliderWidget()]\n' +
diff --git a/IPython/html/widgets/widget_float.py b/IPython/html/widgets/widget_float.py
index 64f2d3b..f7eaf20 100644
--- a/IPython/html/widgets/widget_float.py
+++ b/IPython/html/widgets/widget_float.py
@@ -165,7 +165,8 @@ class _BoundedFloatRange(_FloatRange):
 
 class FloatRangeSlider(_BoundedFloatRange):
     _view_name = Unicode('FloatSliderView', sync=True)
-    orientation = Enum([u'horizontal', u'vertical'], u'horizontal',
+    orientation = CaselessStrEnum(values=['horizontal', 'vertical'], 
+        default_value='horizontal', allow_none=False, 
         help="Vertical or horizontal.", sync=True)
     _range = Bool(True, help="Display a range selector", sync=True)
     readout = Bool(True, help="Display the current value of the slider next to it.", sync=True)
diff --git a/IPython/html/widgets/widget_int.py b/IPython/html/widgets/widget_int.py
index a98692c..1eebe5f 100644
--- a/IPython/html/widgets/widget_int.py
+++ b/IPython/html/widgets/widget_int.py
@@ -169,7 +169,8 @@ class _BoundedIntRange(_IntRange):
 
 class IntRangeSlider(_BoundedIntRange):
     _view_name = Unicode('IntSliderView', sync=True)
-    orientation = Enum([u'horizontal', u'vertical'], u'horizontal',
+    orientation = CaselessStrEnum(values=['horizontal', 'vertical'], 
+        default_value='horizontal', allow_none=False, 
         help="Vertical or horizontal.", sync=True)
     _range = Bool(True, help="Display a range selector", sync=True)
     readout = Bool(True, help="Display the current value of the slider next to it.", sync=True)