Flex中如何通过showAllDataTips属性，使鼠标移动到图表时显示所有的数据Tips

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white" viewSourceURL="srcview/index.html">

    <mx:Script>
        <![CDATA[
            import mx.charts.series.items.PieSeriesItem;
            import mx.charts.HitData;

            private function pieChart_rollOver(evt:MouseEvent):void {
                PieChart(evt.currentTarget).showAllDataTips = true;
            }

            private function pieChart_rollOut(evt:MouseEvent):void {
                PieChart(evt.currentTarget).showAllDataTips = false;
            }

            private function pieChart_dataTipFunction(item:HitData):String {
                var pSI:PieSeriesItem = item.chartItem as PieSeriesItem;
                return "<b>" + pSI.item.@label + "</b><br />" +
                        pSI.item.@data + " (<i>" +
                        pSI.percentValue.toFixed(2) + "%</i>)";
            }
        ]]>
    </mx:Script>

    <mx:XML id="dp">
        <products>
            <product label="Product 1" data="3" />
            <product label="Product 2" data="1" />
            <product label="Product 3" data="4" />
            <product label="Product 4" data="1" />
            <product label="Product 5" data="5" />
            <product label="Product 6" data="9" />
        </products>
    </mx:XML>

    <mx:PieChart id="pieChart"
            dataProvider="{dp.product}"
            dataTipFunction="pieChart_dataTipFunction"
            height="250"
            width="250"
            rollOver="pieChart_rollOver(event);"
            rollOut="pieChart_rollOut(event);">
        <mx:series>
            <mx:PieSeries id="pieSeries"
                    field="@data" />
        </mx:series>
    </mx:PieChart>

</mx:Application>