问Flex 4- Jerky动画问题

EN

<?xml version="1.0" encoding="utf-8"?>
<s:Group xmlns:fx="http://ns.adobe.com/mxml/2009" 
         xmlns:s="library://ns.adobe.com/flex/spark" 
         xmlns:mx="library://ns.adobe.com/flex/mx" width="274" height="72"
         click="onClick()" xmlns:components="ui.hud.components.*" cacheAsBitmap="true">
    <fx:Declarations>
        <!-- Place non-visual elements (e.g., services, value objects) here -->
        <s:Sequence id="tween" repeatCount="5" effectEnd="onEffectEnd()" >
            <s:Move xBy="20" duration="500" />
            <s:Move xBy="-20" duration="500" xFrom="50"/>
        </s:Sequence>
        <s:Fade id="fadeEffect" alphaTo="0" duration="2000" />
    </fx:Declarations>

    <fx:Script>
        <![CDATA[
            [Bindable]
            public var questId:int;
            [Bindable]
            public var questTitle:String;
            [Bindable]
            public var iconUrl:String;

            private function onClick():void{

                Globals.questCtr.showQuest(questId);

            }
            private function onEffectEnd():void{

                fadeEffect.stop();
                fadeEffect.play([lblStatus]);
            }

            public function showProgressEffect():void{

                tween.stop();
                lblStatus.alpha = 1;
                tween.play([lblStatus]);
            }

        ]]>
    </fx:Script>

    <mx:Image source="{iconUrl}" width="75" height="75"/>
    <s:Group x="77" y="24" width="197">
        <s:Label id="lblStatus" text="Task Complete" fontWeight="bold" fontSize="25" alpha="0" cacheAsBitmap="true" hideEffect="" mouseEnabled="false"/>        
    </s:Group>

</s:Group>