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

         */
        public function ensureCellIsVisible(rowIndex:int, columnIndex:int = -1):void
        {
            // be safe
            if (rowIndex < 0)
                return;
            
            // A cell's index as defined by LayoutBase it's just its position
            // in the row-major linear ordering of the grid's cells.
            
            const index:int = (rowIndex * dataProvider.length) + ((columnIndex < 0) ? 0 : columnIndex);
            var spDelta:Point = gridLayout.getScrollPositionDeltaToElement(index);
            if (spDelta)
            {
                if (columnIndex >= 0)
                    horizontalScrollPosition += spDelta.x;
                verticalScrollPosition += spDelta.y;
            }
        }        
        
        /**

        //
        //  GridLayout Cover Methods, Properties
        //
        //-------------------------------------------------------------------------- 
        
        /** 
         *  Update the scroll position so that the virtual Grid element at the specified
         *  index is visible.   Note that getScrollPositionDeltaToElement() is only 
         *  approximate when variableRowHeight=true, so calling this method once will
         *  not necessarily scroll far enough to expose the specified element.
         */
        private function scrollToIndex(elementIndex:int, scrollHorizontally:Boolean):void
        {
            var spDelta:Point = gridLayout.getScrollPositionDeltaToElement(elementIndex);
            if (!spDelta)
                return;  // the specified index is no longer valid, punt
            
            if (scrollHorizontally)
                horizontalScrollPosition += spDelta.x;
            verticalScrollPosition += spDelta.y;
        }
        
        /**
         *  If necessary, set the verticalScrollPosition and horizontalScrollPosition 
