[flexcomponents] Canvas DropShadow effect

[Firdosh Tangri]

I am trying to achieve a dropshadow effect for my Canvas object but I cannot
see the dropshadow.

<mx:Canvas backgroundColor="0x000000" width="90%" height="90%" id="img2"
dropShadowColor="0x666666"
       shadowDirection="center" shadowDistance="10"
dropShadowEnabled="true" cornerRadius="6">

thanks
firdosh