Why doesn't this work?

Hiya

Ok i’m just creating my new portfolio website and something’s completely baffling me.

When I open a new section i’ve got a drop down that pops down and a mask reveals some text, then when the closeBtn is pressed I want the mask to reverse and the box that’s popped down to reverse. Here’s the code:

import mx.transitions.Tween;
import mx.transitions.easing.*;
import flash.display.*;

function moveShizzle(targetFrame)
{
    dropTxt.masker.onEnterFrame = function ()
    {
        if (this._currentframe != targetFrame)
        {
            this.prevFrame();
        }
        else
        {
            delete this.onEnterFrame;
        } // end else if
    };
} // End of the function


var dropDown = new mx.transitions.Tween(dropDown, "_height", mx.transitions.easing.Strong.easeInOut, 1, 270, 50);
    dropDown.onMotionFinished = function (){
        dropTxt.masker.play();
}

dropTxt.closeBtn.onRelease = function (){
moveShizzle (1);
new mx.transitions.Tween(dropDown, "_height", mx.transitions.easing.Strong.easeInOut, 270, 1, 50);

All that happens is the mask reverses, covering up the text, but the box behind it stays exactly where it is?

Any help much appreciated!

Tom