         return null;
     }
     
+    private static var oldContentBackgroundAlpha:Number;
+    private static var contentBackgroundAlphaSetLocally:Boolean;
+
     /**
      *  @private
      */

import flash.display.DisplayObject;
import flash.geom.ColorTransform;

import mx.core.UIComponent;
import mx.core.mx_internal;

import spark.components.supportClasses.Skin;
import spark.core.DisplayObjectSharingMode;
import spark.core.IGraphicElement;
import spark.primitives.supportClasses.GraphicElement;

use namespace mx_internal;

/**
 *  Base class for Spark skins.

    }
    
    /**
     * Names of items that should have their <code>color</code> property defined by the <code>symbolColor</code> style.
     *  
     *  @langversion 3.0
