Stopping motion tween onResize

I have a mask that dynamically adjusts it’s height/width based on the stage size. The mask wipes from left to right. It works fine, until you try and resize the window while the mask is in motion. The mask animation stops as the resize is done and then picks back up, but the tween that determines the mask width still runs in the background, so you get a quick flash of the full mask before the mask wipe is complete.

I am trying to stop the mask tween. Usually a tween.stop(); works fine, but not in this case. I also tried telling the tween to stop on resize, but then it won’t even start when the movie is loaded. Thanks for any help. Here’s a link to the movie:

www.jordangreenwood.com/testfullscreen

code:

stageListener = new Object();
stageListener.onResize = function() {

expandMask();
expandAnim();

}

Stage.addListener(stageListener);

expandMask = function() {
pic_mask._height = Stage.height;
}

expandAnim = function() {
import mx.transitions.Tween;
import mx.transitions.easing.*;
var Mask:Tween = new Tween (pic_mask,"_xscale", Strong.easeInOut, getProperty(pic_mask, _width),(Stage.width)+100,60,false);

Mask.onMotionFinished = function() {
gotoAndStop(26);
}
}

stageListener.onResize();