diff --git a/IPython/html/widgets/widget.py b/IPython/html/widgets/widget.py
index df69558..831e762 100644
--- a/IPython/html/widgets/widget.py
+++ b/IPython/html/widgets/widget.py
@@ -30,8 +30,6 @@ class Widget(LoggingConfigurable):
     widget_construction_callback = None
     widgets = {}
 
-    keys = ['view_name'] # TODO: Sync = True
-
     def on_widget_constructed(callback):
         """Class method, registers a callback to be called when a widget is
         constructed.  The callback must have the following signature:
@@ -49,7 +47,7 @@ class Widget(LoggingConfigurable):
     model_name = Unicode('widget', help="""Name of the backbone model 
         registered in the front-end to create and sync this widget with.""")
     view_name = Unicode(help="""Default view registered in the front-end
-        to use to represent the widget.""")
+        to use to represent the widget.""", sync=True)
 
     @contextmanager
     def property_lock(self, key, value):
@@ -69,6 +67,15 @@ class Widget(LoggingConfigurable):
         return key != self._property_lock[0] or \
         value != self._property_lock[1]
 
+    @property
+    def keys(self):
+        if self._keys is None:
+            self._keys = []
+            for trait_name in self.trait_names():
+                if self.trait_metadata(trait_name, 'sync'):
+                    self._keys.append(trait_name)
+        return self._keys
+
     # Private/protected declarations
     _comm = Instance('IPython.kernel.comm.Comm')
     
@@ -79,6 +86,7 @@ class Widget(LoggingConfigurable):
         self._property_lock = (None, None)
         self._display_callbacks = []
         self._msg_callbacks = []
+        self._keys = None
         super(Widget, self).__init__(**kwargs)
 
         self.on_trait_change(self._handle_property_changed, self.keys)
diff --git a/IPython/html/widgets/widget_bool.py b/IPython/html/widgets/widget_bool.py
index f2984c0..e67efb3 100644
--- a/IPython/html/widgets/widget_bool.py
+++ b/IPython/html/widgets/widget_bool.py
@@ -24,8 +24,7 @@ class BoolWidget(DOMWidget):
     view_name = Unicode('CheckboxView')
 
     # Model Keys
-    keys = ['value', 'description', 'disabled'] + DOMWidget.keys
-    value = Bool(False, help="Bool value")
-    description = Unicode('', help="Description of the boolean (label).") 
-    disabled = Bool(False, help="Enable or disable user changes.")
+    value = Bool(False, help="Bool value", sync=True)
+    description = Unicode('', help="Description of the boolean (label).", sync=True) 
+    disabled = Bool(False, help="Enable or disable user changes.", sync=True)
     
\ No newline at end of file
diff --git a/IPython/html/widgets/widget_button.py b/IPython/html/widgets/widget_button.py
index adce730..0f09381 100644
--- a/IPython/html/widgets/widget_button.py
+++ b/IPython/html/widgets/widget_button.py
@@ -28,9 +28,8 @@ class ButtonWidget(DOMWidget):
     view_name = Unicode('ButtonView')
 
     # Keys
-    keys = ['description', 'disabled'] + DOMWidget.keys
-    description = Unicode('', help="Description of the button (label).")
-    disabled = Bool(False, help="Enable or disable user changes.")
+    description = Unicode('', help="Description of the button (label).", sync=True)
+    disabled = Bool(False, help="Enable or disable user changes.", sync=True)
     
 
     def __init__(self, **kwargs):
diff --git a/IPython/html/widgets/widget_container.py b/IPython/html/widgets/widget_container.py
index ae89546..049f8f3 100644
--- a/IPython/html/widgets/widget_container.py
+++ b/IPython/html/widgets/widget_container.py
@@ -25,8 +25,7 @@ class ContainerWidget(DOMWidget):
 
     # Keys, all private and managed by helper methods.  Flexible box model
     # classes...
-    keys = ['description', 'button_text', 'children'] + DOMWidget.keys # TODO: Use add/remove_class
-    children = List(Instance(DOMWidget))
+    children = List(Instance(DOMWidget), sync=True)
     
-    description = Unicode()
-    button_text = Unicode()
+    description = Unicode(sync=True)
+    button_text = Unicode(sync=True)
diff --git a/IPython/html/widgets/widget_float.py b/IPython/html/widgets/widget_float.py
index c4b9f8b..e2ff8e3 100644
--- a/IPython/html/widgets/widget_float.py
+++ b/IPython/html/widgets/widget_float.py
@@ -24,7 +24,6 @@ class FloatWidget(DOMWidget):
     view_name = Unicode('FloatTextView')
 
     # Keys
-    keys = ['value', 'disabled', 'description'] + DOMWidget.keys
-    value = Float(0.0, help="Float value") 
-    disabled = Bool(False, help="Enable or disable user changes")
-    description = Unicode(help="Description of the value this widget represents")
+    value = Float(0.0, help="Float value", sync=True) 
+    disabled = Bool(False, help="Enable or disable user changes", sync=True)
+    description = Unicode(help="Description of the value this widget represents", sync=True)
diff --git a/IPython/html/widgets/widget_float_range.py b/IPython/html/widgets/widget_float_range.py
index 4326338..1105c06 100644
--- a/IPython/html/widgets/widget_float_range.py
+++ b/IPython/html/widgets/widget_float_range.py
@@ -24,11 +24,10 @@ class FloatRangeWidget(DOMWidget):
     view_name = Unicode('FloatSliderView')
 
     # Keys
-    keys = ['value', 'step', 'max', 'min', 'disabled', 'orientation', 'description'] + DOMWidget.keys
-    value = Float(0.0, help="Float value") 
-    max = Float(100.0, help="Max value")
-    min = Float(0.0, help="Min value")
-    disabled = Bool(False, help="Enable or disable user changes")
-    step = Float(0.1, help="Minimum step that the value can take (ignored by some views)")
-    orientation = Unicode(u'horizontal', help="Vertical or horizontal (ignored by some views)")
-    description = Unicode(help="Description of the value this widget represents")
+    value = Float(0.0, help="Float value", sync=True) 
+    max = Float(100.0, help="Max value", sync=True)
+    min = Float(0.0, help="Min value", sync=True)
+    disabled = Bool(False, help="Enable or disable user changes", sync=True)
+    step = Float(0.1, help="Minimum step that the value can take (ignored by some views)", sync=True)
+    orientation = Unicode(u'horizontal', help="Vertical or horizontal (ignored by some views)", sync=True)
+    description = Unicode(help="Description of the value this widget represents", sync=True)
diff --git a/IPython/html/widgets/widget_image.py b/IPython/html/widgets/widget_image.py
index d7557b7..7442fe7 100644
--- a/IPython/html/widgets/widget_image.py
+++ b/IPython/html/widgets/widget_image.py
@@ -27,11 +27,10 @@ class ImageWidget(DOMWidget):
     view_name = Unicode('ImageView')
     
     # Define the custom state properties to sync with the front-end
-    keys = ['format', 'width', 'height', '_b64value'] + DOMWidget.keys
-    format = Unicode('png')
-    width = Unicode() # TODO: C unicode
-    height = Unicode()
-    _b64value = Unicode()
+    format = Unicode('png', sync=True)
+    width = Unicode(sync=True) # TODO: C unicode
+    height = Unicode(sync=True)
+    _b64value = Unicode(sync=True)
     
     value = Bytes()
     def _value_changed(self, name, old, new):
diff --git a/IPython/html/widgets/widget_int.py b/IPython/html/widgets/widget_int.py
index e03dafb..d7c255d 100644
--- a/IPython/html/widgets/widget_int.py
+++ b/IPython/html/widgets/widget_int.py
@@ -24,7 +24,6 @@ class IntWidget(DOMWidget):
     view_name = Unicode('IntTextView')
 
     # Keys
-    keys = ['value', 'disabled', 'description'] + DOMWidget.keys
-    value = Int(0, help="Int value") 
-    disabled = Bool(False, help="Enable or disable user changes")
-    description = Unicode(help="Description of the value this widget represents")
+    value = Int(0, help="Int value", sync=True) 
+    disabled = Bool(False, help="Enable or disable user changes", sync=True)
+    description = Unicode(help="Description of the value this widget represents", sync=True)
diff --git a/IPython/html/widgets/widget_int_range.py b/IPython/html/widgets/widget_int_range.py
index 819bc4a..9aa9d11 100644
--- a/IPython/html/widgets/widget_int_range.py
+++ b/IPython/html/widgets/widget_int_range.py
@@ -24,11 +24,10 @@ class IntRangeWidget(DOMWidget):
     view_name = Unicode('IntSliderView')
 
     # Keys
-    keys = ['value', 'step', 'max', 'min', 'disabled', 'orientation', 'description'] + DOMWidget.keys
-    value = Int(0, help="Int value") 
-    max = Int(100, help="Max value")
-    min = Int(0, help="Min value")
-    disabled = Bool(False, help="Enable or disable user changes")
-    step = Int(1, help="Minimum step that the value can take (ignored by some views)")
-    orientation = Unicode(u'horizontal', help="Vertical or horizontal (ignored by some views)")
-    description = Unicode(help="Description of the value this widget represents")
+    value = Int(0, help="Int value", sync=True) 
+    max = Int(100, help="Max value", sync=True)
+    min = Int(0, help="Min value", sync=True)
+    disabled = Bool(False, help="Enable or disable user changes", sync=True)
+    step = Int(1, help="Minimum step that the value can take (ignored by some views)", sync=True)
+    orientation = Unicode(u'horizontal', help="Vertical or horizontal (ignored by some views)", sync=True)
+    description = Unicode(help="Description of the value this widget represents", sync=True)
diff --git a/IPython/html/widgets/widget_selection.py b/IPython/html/widgets/widget_selection.py
index 91256d6..b477bc9 100644
--- a/IPython/html/widgets/widget_selection.py
+++ b/IPython/html/widgets/widget_selection.py
@@ -24,9 +24,8 @@ class SelectionWidget(DOMWidget):
     view_name = Unicode('DropdownView')
 
     # Keys
-    keys = ['value', 'values', 'disabled', 'description'] + DOMWidget.keys
-    value = Unicode(help="Selected value") # TODO: Any support
-    values = List(help="List of values the user can select")
-    disabled = Bool(False, help="Enable or disable user changes")
-    description = Unicode(help="Description of the value this widget represents")
+    value = Unicode(help="Selected value", sync=True) # TODO: Any support
+    values = List(help="List of values the user can select", sync=True)
+    disabled = Bool(False, help="Enable or disable user changes", sync=True)
+    description = Unicode(help="Description of the value this widget represents", sync=True)
  
\ No newline at end of file
diff --git a/IPython/html/widgets/widget_selectioncontainer.py b/IPython/html/widgets/widget_selectioncontainer.py
index efb0ba8..d941621 100644
--- a/IPython/html/widgets/widget_selectioncontainer.py
+++ b/IPython/html/widgets/widget_selectioncontainer.py
@@ -25,9 +25,8 @@ class SelectionContainerWidget(DOMWidget):
     view_name = Unicode('TabView')
 
     # Keys
-    keys = ['_titles', 'selected_index', 'children'] + DOMWidget.keys
-    _titles = Dict(help="Titles of the pages")
-    selected_index = Int(0)
+    _titles = Dict(help="Titles of the pages", sync=True)
+    selected_index = Int(0, sync=True)
 
     children = List(Instance(DOMWidget))
 
diff --git a/IPython/html/widgets/widget_string.py b/IPython/html/widgets/widget_string.py
index 35c099a..4b8d27a 100644
--- a/IPython/html/widgets/widget_string.py
+++ b/IPython/html/widgets/widget_string.py
@@ -27,10 +27,9 @@ class StringWidget(DOMWidget):
     view_name = Unicode('TextBoxView')
 
     # Keys
-    keys = ['value', 'disabled', 'description'] + DOMWidget.keys
-    value = Unicode(help="String value")
-    disabled = Bool(False, help="Enable or disable user changes")
-    description = Unicode(help="Description of the value this widget represents")
+    value = Unicode(help="String value", sync=True)
+    disabled = Bool(False, help="Enable or disable user changes", sync=True)
+    description = Unicode(help="Description of the value this widget represents", sync=True)
 
 
     def __init__(self, **kwargs):