Flex editable datagrid with itemEditor "combobox" not auto scroll when I edit a cell

I have a flex datagrid with dynamic columns (matrix 60 x 60 by sample) and each cell is a "combobox". My problem is when the vertical scroll position moves through any row following. How can I control this erro开发者_StackOverflow中文版r? How can I use "verticalScrollPosition"????

<mx:DataGrid height="100%" id="dgLineRanges" editable="{editable}" itemEditBegin="modifyEditedData(event);" itemEditEnd="saveEditedData(event);" horizontalScrollPolicy="auto" visible="false"/>

I use this code:

// Handle the itemEditBegin event.
        private function modifyEditedData(event:DataGridEvent):void
        {    
           // Handle the event here.
            event.preventDefault();

            // El triangulo inferior no es editable
            if(event.columnIndex > 0 && event.columnIndex > event.rowIndex)
            {
                //Buscar el rango que corresponde y actualizar su valor
                selectedCell = dgLineRanges.dataProvider.getItemAt(event.rowIndex).getItemAt(event.columnIndex);

                // Creates an item editor.                
                dgLineRanges.createItemEditor(event.columnIndex,event.rowIndex);

                // All item editors must implement the IDropInListItemRenderer interface
                // and the listData property. 
                // Initialize the listData property of the editor. 
                IDropInListItemRenderer(dgLineRanges.itemEditorInstance).listData =
                    IDropInListItemRenderer(dgLineRanges.editedItemRenderer).listData;

                // Copy the cell value to the TextInput control.
                dgLineRanges.itemEditorInstance.data = dgLineRanges.editedItemRenderer.data;

                // Copy the cell value to the RangeComboItemEditor control.
                var rangeCombo:RangeComboItemEditor = dgLineRanges.itemEditorInstance as RangeComboItemEditor;

                // Sólo permitimos editar si está prohibido (pero puede permitirlo)
                rangeCombo.editable = !selectedCell.forbidden;

                // Esta variable se tiene en cuenta a la hora de habilitar o no los botomes de prohibido 
                enableForbidden(true);

                // Establecer el foco
                model.setRangeComboIEFocus(rangeCombo, !selectedCell.forbidden);
            }
            else
            {
                enableForbidden(false);
            }
        }


        private function saveEditedData(event:DataGridEvent):void
        {
            // Check the reason for the event.
            if (event.reason == DataGridEventReason.CANCELLED || event.columnIndex == 0)
            {
                // Do not update cell.
                return;
            }

            // Guardamos indices de cela para facilitar posible tratamiento de botones
            // prohibido / permitodo
            lastRowIndex = event.rowIndex;
            lastColumnIndex = event.columnIndex;

            //Buscar el rango que corresponde
            var stopsRange:FareOriginDestDTO = dgLineRanges.dataProvider.getItemAt(event.rowIndex).getItemAt(event.columnIndex);

            if(stopsRange.saveAction == IfsConst.SAVE_ACTION_NONE)
                stopsRange.saveAction = IfsConst.SAVE_ACTION_UPDATE;


            // Get the new data value from the editor.
            var newRangeCode:int= event.currentTarget.itemEditorInstance.code;

            //Actualizar su valor
            stopsRange.rangeCode = newRangeCode;

            //Actualizar "Forbidden"
            if (newRangeCode == -1)
                stopsRange.forbidden = true;
            else
                stopsRange.forbidden = false;


            // Simétrico (si no está en la diagonal)
            if( event.rowIndex != event.columnIndex-1 )
            {
                stopsRange = dgLineRanges.dataProvider.getItemAt(event.columnIndex-1).getItemAt(event.rowIndex+1);

                // Solo se cambia la celda simétrica si:
                //  Celda principal es "Forbidden" y la simétrica también
                //  Celda principal no es "Forbidden"                   
                if ((newRangeCode == -1 && stopsRange.rangeCode == -1) || newRangeCode != -1)
                {
                    if (stopsRange.saveAction == IfsConst.SAVE_ACTION_NONE)
                        stopsRange.saveAction = IfsConst.SAVE_ACTION_UPDATE;    
                    stopsRange.rangeCode = newRangeCode;
                }
            }

            // Close the cell editor.
            dgLineRanges.destroyItemEditor();

            // Notify the list control to update its display.
            dgLineRanges.dataProvider.itemUpdated(event.itemRenderer.data);

            // Mandatory dataProvider refresh
            dgLineRanges.dataProvider.refresh();                

            // Disable copying data back to the control.
            //event.preventDefault();
        }