Scaling on-screen textfield by dragging in runtime

1

hi
I am trying to make a textfield which could be resized as desired. I have managed to achieve this. But the dragging of the movieclip that acts as the scrubber on the bottom of right-hand corner causes a lag in the resizing of the textfield itself.
Is there any way to fix this.
Thanks in advance for your help. The code is as below. Alos attaching the fla.


scrub.alpha=0;
scrub.addEventListener(MouseEvent.MOUSE_OVER, showScrub)
scrub.addEventListener(MouseEvent.MOUSE_OUT, hideScrub)
function showScrub(e:MouseEvent){
    scrub.alpha=1;
    scrub.addEventListener(MouseEvent.MOUSE_DOWN,dragScrub)
    scrub.addEventListener(MouseEvent.MOUSE_UP,unDragScrub)
}
function dragScrub(e:MouseEvent){
    scrub.startDrag();
    scrub.addEventListener(Event.ENTER_FRAME, update);
}
function unDragScrub(e:MouseEvent){
    scrub.stopDrag();
}
function hideScrub(e:MouseEvent){
    scrub.alpha=0;
}

function update(e:Event){
    
    var mousex = scrub.x;
    var mousey = scrub.y;
    var mcX = mc.x;
    var mcY = mc.y;
    var projectedWidth = mousex-mcX;
    var projectedHeight = mousey-mcY;
    mc.width = projectedWidth;
    mc.txt.width = mc.width;
    mc.height = projectedHeight;
    mc.txt.height = mc.height;
    trace(projectedWidth)
}