Scale flex application

I’m new to flex, and I search a way to scale entire flex application (or a
function àuser can zoom with slider the application in the browser to fit).
My application is 1024x 768, good fit on laptop but on the big screen, is
too small.

On my computer the crtl+ or ctrl- work well to zoom on explorer and chrome
(but on some others computers this function not working on flash??

Other way, when I use the zoom in the flash context menu, it is to big and
not fit in the windows.

I try this function , but not working when the windows increase.

<s:Application addedToStage="stretchHandler()"/>

private function stretchHandler():void{

stage.scaleMode = StageScaleMode.SHOW_ALL;

stage.align = StageAlign.TOP;

this.width = stage.stageWidth;

this.height = stage.stageHeight;

Pierre