Fondo adaptable

[Aleks1]

Hola buenas, que tal; Os cuento mi problema con esto llevo ya mas de 70 horas intentandolo pero no hay manera de hacerlo.

Genero un clip y lo pinto con beginGradientFil, luego como quiero que cambie de color el degradado cuando pulse un boton, he recogido un codigo de internet que genera rgb a exadeimales, el problema viene que cuando redimensiono pantalla el color se pierde hasta que no le de otra vez al boton. Os pongo el codigo:

Código ActionScript:

//////////////////
import mx.transitions.Tween;
import mx.transitions.easing.*;
Stage.scaleMode = "noScale";
Stage.align = "TL";
/////// variables
a = Stage.width;
b = Stage.height;
 
///////////////////
var miListener:Object = new Object();
creafons();
 
////////////////
function creafons(Fondo:MovieClip, angle:Number, from:Number, to:Number) {
    Fondo.firstColor = from;
    Fondo.secondColor = to;
    createEmptyMovieClip("Fondo",1);
    import flash.geom.*;
    var fillType:String = "linear";
    var angle:Number = angle || 90;
    var colors:Array = [from, to];
    var alphas:Array = [50, 50];
    var ratios:Array = [127, 255];
    var matrix:Matrix = new Matrix();
    matrix.createGradientBox(a,a,0,0,0);
    var spreadMethod:String = "pad";
    Fondo.beginGradientFill(fillType,colors,alphas,ratios,matrix,spreadMethod);
    Fondo.lineTo(0,25);
    Fondo.lineTo(0,b);
    Fondo.lineTo(a,b);
    Fondo.lineTo(a,0);
    Fondo.endFill();
 
}
/////////////////////
function tweenGradientFondo(what:MovieClip, c1:Number, c2:Number, time:Number) {
    what.percent.stop;
    delete what.percent;
    var holder:Object = new Object();
    holder.percent = 0;
    ///first color///
    var red:Number = what.firstColor >>> (4*4) & 0xFF;
    var green:Number = what.firstColor >>> (2*4) & 0xFF;
    var blue:Number = what.firstColor >>> (0*4) & 0xFF;
    var toRed:Number = c1 >>> (4*4) & 0xFF;
    var toGreen:Number = c1 >>> (2*4) & 0xFF;
    var toBlue:Number = c1 >>> (0*4) & 0xFF;
    var redDiff:Number = (toRed-red)/100;
    var greenDiff:Number = (toGreen-green)/100;
    var blueDiff:Number = (toBlue-blue)/100;
    ///second color///
    var red2:Number = what.secondColor >>> (4*4) & 0xFF;
    var green2:Number = what.secondColor >>> (2*4) & 0xFF;
    var blue2:Number = what.secondColor >>> (0*4) & 0xFF;
    var toRed2:Number = c2 >>> (4*4) & 0xFF;
    var toGreen2:Number = c2 >>> (2*4) & 0xFF;
    var toBlue2:Number = c2 >>> (0*4) & 0xFF;
    var redDiff2:Number = (toRed2-red2)/100;
    var greenDiff2:Number = (toGreen2-green2)/100;
    var blueDiff2:Number = (toBlue2-blue2)/100;
 
    what.percent = new Tween(holder, "percent", None.easeNone, 0, 100, time, true);
    what.percent.onMotionChanged = function() {
        ///FIRST COLOR///
        var r = red+(redDiff*holder.percent);
        var g = green+(greenDiff*holder.percent);
        var b = blue+(blueDiff*holder.percent);
        what.firstColor = (r << (4*4)) | (g << (2*4)) | (b << (0*4));
        ///
        ///SECOND COLOR///
        var r2 = red2+(redDiff2*holder.percent);
        var g2 = green2+(greenDiff2*holder.percent);
        var b2 = blue2+(blueDiff2*holder.percent);
        what.secondColor = (r2 << (4*4)) | (g2 << (2*4)) | (b2 << (0*4));
        ////set new gradient
        creafons(what,90,what.firstColor,what.secondColor);
 
    };
}
/////////////////////
Stage.addListener(miListener);
miListener.onResize = function() {
    a = Stage.width;
    b = Stage.height;
    creafons();
};
///////////////////
boto.onPress =function() {
    tweenGradientFondo(Fondo,0xffffff*Math.random(),0xffffff*Math.random(),1);
}
 

No se porque se pierde la información de la variable, a ver si alguien me puede hechar un cable, gracias.