flex LineChart 图表动态增删Y轴实现。实现了动态增加但是Y轴删不干净

现在实现了动态增加Y轴但是在移除的时候出现了问题，Y轴删不干净，我快疯了，以下是样例代码，求助。

 

 

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute">
<mx:Script>
<![CDATA[
import mx.collections.ArrayCollection;

[Bindable]
private var medalsAC:ArrayCollection = new ArrayCollection( [
{ Country: "USA", Gold: 35, Silver:39,Bronze:66,Bronze1:44 },
{ Country: "China", Gold: 32, Silver:17,Bronze:47,Bronze1:97 },
{ Country: "Russia", Gold: 27, Silver:27,Bronze:33,Bronze1:45 } ]);

private function leftclick(event:MouseEvent):void{
first1.visible=!first1.visible;
first2.visible=!first2.visible;
first3.visible=!first3.visible;
}
private function rightclick(event:MouseEvent):void{
second1.visible=!second1.visible;
second2.visible=!second2.visible;
second3.visible=!second3.visible;
}


private var vaxarr:Array = new Array();
protected function button1_clickHandler(event:MouseEvent):void
{


var vax:AxisRenderer = new AxisRenderer();

var linearaxis:LinearAxis = new LinearAxis();
vax.axis = linearaxis;
vaxarr.push(vax);
LineChart.verticalAxisRenderers= vaxarr;

}


protected function button2_clickHandler(event:MouseEvent):void
{
vaxarr.pop();
LineChart.verticalAxisRenderers= vaxarr;
}

]]>
</mx:Script>
<mx:LineChart id="LineChart" dataProvider="{medalsAC}" showDataTips="true" width="500" height="300" y="0" x="0">
<mx:horizontalAxis>
<mx:CategoryAxis categoryField="Country" />
</mx:horizontalAxis>
<mx:series>
<mx:LineSeries id="first1" verticalAxis="{firstVAxis}" displayName="左边1" yField="Gold" itemRenderer="mx.charts.renderers.CircleItemRenderer">
</mx:LineSeries>
<mx:LineSeries id="first2" verticalAxis="{firstVAxis}" yField="Silver" displayName="左边2" itemRenderer="mx.charts.renderers.CircleItemRenderer">
</mx:LineSeries>
<mx:LineSeries id="second1" verticalAxis="{secondVAxis}" yField="Bronze" displayName="右边1" itemRenderer="mx.charts.renderers.CircleItemRenderer">
</mx:LineSeries>
<mx:LineSeries id="second2" verticalAxis="{secondVAxis}" yField="Bronze1" displayName="右边2" itemRenderer="mx.charts.renderers.CircleItemRenderer">
</mx:LineSeries>
</mx:series>
<mx:verticalAxisRenderers>
<mx:AxisRenderer placement="left" color="#FF0000" id="first3" >
<mx:axis>
<mx:LinearAxis title="" baseAtZero="true" id="firstVAxis"/>
</mx:axis>
</mx:AxisRenderer>
<mx:AxisRenderer placement="right" color="#FFFF00" id="second3">
<mx:axis>
<mx:LinearAxis title="" baseAtZero="true" id="secondVAxis"/>
</mx:axis>
</mx:AxisRenderer>
</mx:verticalAxisRenderers>
</mx:LineChart>
<mx:Button x="553" y="448" label="隐藏左边" click="leftclick(event)" fontSize="12"/>
<mx:Button x="553" y="448" label="隐藏右边" click="rightclick(event)" fontSize="12"/>
<mx:Button x="553" y="208" label="添加轴" click="button1_clickHandler(event)"/>
<mx:Button x="553" y="238" label="移除加轴" click="button2_clickHandler(event)"/>
</mx:Application>