     //  Properties
     //
     //--------------------------------------------------------------------------
+
+    //----------------------------------
+    //  autoGroupIndex
+    //----------------------------------
+
+    /**
+     *  @private
+     *  automaticRadioButtonGroups is shared with halo radio button groups.
+     *  Spark radio button groups are prefixed with _fx to differentiate the
+     *  Halo groups which are stored in the same table.
+     */
+    private function get autoGroupIndex():String
+    {
+        return "_spark_" + groupName;
+    }
 
     //----------------------------------
     //  group

            addToGroup();

        var g:RadioButtonGroup = group;
        if (g.selection != this)
            g.setSelection(this);
    }

    //--------------------------------------------------------------------------
    //
    //  Overridden functions: UIComponent
    //
    //--------------------------------------------------------------------------

    /**
     *  @private
     */
    override protected function updateDisplayList(unscaledWidth:Number,
                                                  unscaledHeight:Number):void
    {
        super.updateDisplayList(unscaledWidth, unscaledHeight);

        // If this rb is selected and in a group, make sure it is the group
        // selection.  If it is not selected and it's in a group, make sure it
        // is not the group selection.
        if (group)
        {
            if (selected)
                _group.selection = this;
            else if (group.selection == this)
                _group.selection = null;   
        }
    }
    
    //--------------------------------------------------------------------------
    //
    //  Overridden event handlers: UIComponent


    /**
     *  @private
     */
    override protected function initializeAccessibility():void
    {
        if (RadioButton.createAccessibilityImplementation != null)
            RadioButton.createAccessibilityImplementation(this);
    }

    /**
     *  @private
     *  Update properties before measurement/layout.
     */
    override protected function commitProperties():void
