Problem with FullScreen and Browser Windows

[SIZE=3][COLOR=#000000][FONT=Calibri]Hi,[/FONT][/COLOR][/SIZE]
[SIZE=3][COLOR=#000000][FONT=Calibri]When I open my apli the FullScreen by default works very well.[/FONT][/COLOR][/SIZE]
[SIZE=3][COLOR=#000000][FONT=Calibri] the problem is when I click to open Windows browser to choose a .txt file I lost FULL_SCREEN and changes in NORMAL mode [/FONT][/COLOR][/SIZE]
[SIZE=3][COLOR=#000000][FONT=Calibri]How to keep(guard) in FULL_SCREEN?[/FONT][/COLOR][/SIZE]
[COLOR=#000000][FONT=Calibri][SIZE=3]Thank you in advance and thank you for your help(assistant)


import gs.TweenLite;
import gs.*;
import gs.easing.*;
import flash.display.MovieClip;
//
var mFileReference:FileReference;
//
rectFond.addChild(ouvreFichier);
ouvreFichier.x = 0;
ouvreFichier.y = 0;
ouvreFichier.buttonMode = true;
ouvreFichier.addEventListener(MouseEvent.CLICK, ouvreExplorer);
//------------------------------------------------------;
fullscreen_mc.buttonMode = true;
fullscreen_mc.addEventListener(MouseEvent.CLICK, goFullScreen);
//------------------------------------------------------;
function ouvreExplorer(event:MouseEvent):void
{
 trace("ouvreExplorer");
 mFileReference=new FileReference();
 mFileReference.addEventListener(Event.SELECT, selectFichier);
 var swfTypeFilter:FileFilter = new FileFilter("Text Files","*.txt");
 var allTypeFilter:FileFilter = new FileFilter("All Files (*.*)","*.*");
 mFileReference.browse([swfTypeFilter, allTypeFilter]);
}
//------------------------------------------------------;
// Cette fonction est appelée quand l'utilisateur selectionne un ficher dans la fenetre explorer;
function selectFichier(event:Event):void
{
 stage.scaleMode = StageScaleMode.NO_SCALE;
 trace("onFileSelected");
}
//
//stage.displayState = StageDisplayState.FULL_SCREEN_INTERACTIVE;
//------------------------------------------------------
stage.displayState = StageDisplayState.FULL_SCREEN;
stage.scaleMode = StageScaleMode.NO_SCALE;
// Ajouter un listener au stage
stage.addEventListener(Event.RESIZE, resizeHandler);
function resizeHandler(e:Event):void
{
 // Centrer  rectFond
 TweenLite.to(rectFond, 1.8, {alpha:1.0, y:(stage.stageHeight/2), x:(stage.stageWidth/2), ease:Back.easeOut, delay:0.2, onComplete:onFinishTween5, onCompleteParams:[1.8, rectFond]});
 function onFinishTween5(parameter1:Number, parameter2:MovieClip):void
 {
  trace("rectFond centrer: " + parameter1 + ", and " + parameter2);
 }
 // FullScreen_mc  en haut a droite
 TweenLite.to(fullscreen_mc, 1.0, {alpha:2.0, y:2, x:(stage.stageWidth - 35), ease:Back.easeOut, delay:0.2, onComplete:onFinishTween13, onCompleteParams:[1.8, fullscreen_mc]});
 function onFinishTween13(parameter1:Number, parameter2:MovieClip):void
 {
  trace("mc FullScreen " + parameter1 + ", and " + parameter2);
 }
}
//
 
function goFullScreen(evt:MouseEvent):void
{
 if (stage.displayState == StageDisplayState.FULL_SCREEN)
 {
  stage.displayState = StageDisplayState.NORMAL;
 }
 else
 {
  stage.displayState = StageDisplayState.FULL_SCREEN;
 }
}
stage.align = StageAlign.TOP_LEFT;
stage.scaleMode = StageScaleMode.NO_SCALE;
stage.dispatchEvent(new Event(Event.RESIZE));
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