         private var _alpha:Number = 1.0;
         
         /**
-         *  The alpha for this design layer instance.
+         *  The alpha for this design layer instance, between 0.0 and 1.0.
          *
          *  <p>When updated, the appropriate change event for <code>effectiveAlpha</code> 
          *  will be dispatched to all <code>layerPropertyChange</code> listeners 

        //----------------------------------
        
        /**
         *  Returns the effective visibility of this design layer (which considers 
         *  the visibility of this layer as well as any ancestor layers).  
         * 
         *  @default true
         * 

        //----------------------------------
        
        /**
         *  Property that returns the effective alpha, between 0.0 and 1.0,
         *  of this design layer. 
         *  This value multiplies the alpha of this layer by the alpha of 
         *  any ancestor layers.  
         * 
         *  @default 1.0
         * 
