Problem in tweening

1

I am trying to create this type of menu tweening http://www.flashmo.com/preview/flashmo_258_dark_focus
on mouseOver my code is

TweenLite.to((evt.target as MovieClip).red,0.5,{x:0 ,width:evt.target.width ,ease:Back.easeInOut })

and on mouse out

TweenLite.to((evt.target as MovieClip).red,0.5,{x:0 ,width:evt.target.width ,ease:Back.easeInOut })

but the problem is everytime I roll over and roll out , Box width is increased.