在Flex中使用带有HDividedBox的ColorMatrixFilter

我当前的代码如下:;灰色滤镜没有效果。

<mx:HDividedBox id="dividedBox" horizontalScrollPolicy="off"
        width="100%" height="100%" 
        liveDragging="true" >
    <mx:Canvas id="leftBox" backgroundColor="#FFFFFF" 
            backgroundAlpha="0.5" width="50%" 
            height="100%" />
    <mx:Canvas backgroundColor="#FFFFFF" backgroundAlpha="0" 
            width="50%" height="100%" buttonMode="true"   
            mouseDown="setMouseDown(rangeChart);" 
            minWidth="{rangeDataRatio * 4}"
    mouseUp="showAnnotations = true; refreshAnnotations()"/>
<mx:Canvas id="rightBox" backgroundColor="#FFFFFF" 
    backgroundAlpha="0.5" width="0%" height="100%"
    filters="{[greyFilter]}" />
</mx:HDividedBox>

过滤代码如下:

var greyMatrix:Array = [ 
    1,1,1,0,0,
    1,1,1,0,0,
    1,1,1,0,0,
    0,0,0,1,0 ];

var greyFilter:ColorMatrixFilter = 
    new ColorMatrixFilter(greyMatrix);