Mask not working on loaded jpg

Question

Hi,
I have a blank movie called "shell" on a frame, which is
where I load the jpg. - shell.loadMovie("1.jpg");
Above that the frame that contains the shell movie, I have a
mask layer. Once the jpg is loaded, I have a shape animation on the
mask layer that reveals the jpg.... but for some reason it doesn't
work. If I take away the mask layer it displays properly.
*UPDATE*
The mask stops working when the shape tween starts. Initialy
the masks works when there is no tween on the mask layer.

Answer 1

Thanks - your example worked for me. Not sure why I couldn't get it to work before. I think it was because the mask and the item were the same exact size as well. I created another example and posted below which is what I was going for.
<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
    layout="absolute">
    <mx:Canvas width="300" height="30" horizontalCenter="0" verticalCenter="0">
        <mx:ProgressBar
            id="prog"
            label="1234"
            width="300"
            height="30"
            indeterminate="true"
            labelPlacement="center"
            mask="{maskCanvas}"/>
        <mx:Canvas
            id="maskCanvas"
            width="295"
            height="20"
            backgroundColor="#000000"
            borderColor="#000000"
            borderStyle="solid"
            cornerRadius="10" horizontalCenter="0" verticalCenter="0"/>
    </mx:Canvas>
</mx:Application>