     }
     
     //----------------------------------
-    //  virtualLayout
-    //----------------------------------
-
-    private var _virtualLayout:Boolean = false;
+    //  useVirtualLayout
+    //----------------------------------
+
+    private var _useVirtualLayout:Boolean = false;
 
     [Inspectable(defaultValue="false")]
 

     *  Used by layouts when fixed row/column sizes are requested but
     *  a specific size isn't specified.
     * 
     *  Used by virtualLayouts to estimate the size of layout elements
     *  that have not been scrolled into view.
     * 
     *  If this property has not been set and the target is non-null 

            return 0;

        var delta:Number = 0;
        switch (scrollUnit)
        {
            case ScrollUnit.UP:
                // Snap the top edge of element to the top edge of the scrollRect.
