     import spark.components.supportClasses.CellPosition;
     import spark.components.supportClasses.GridColumn;
     import spark.components.supportClasses.GridDimensions;
+    import spark.components.supportClasses.GridLayer;    
     import spark.components.supportClasses.GridLayout;
     import spark.components.supportClasses.GridSelection;
     import spark.components.supportClasses.GridSelectionMode;

        }
    }
}

import spark.layouts.supportClasses.LayoutBase;

class NullLayout extends LayoutBase
{
    public function NullLayout()
    {
        super();
    }
}
        
        /**
         *  @private
         *  True while updateDisplayList is running.  Use to disable invalidateSize(),
         *  invalidateDisplayList() here and in the GridLayer class.
         */
        mx_internal var inUpdateDisplayList:Boolean = false;  
        
        
        // TODO(hmuller): the following public variables are temporary 
