Bug scale on Mozilla Firefox Windows 8.1

Question

Hello,
I have a strange bug on Mozilla Firefox or in Google Chrome npapi on Windows 8.1, not on Windows XP
ie, Google Chrome ppapi works fine
package{
  import flash.display.Sprite;
  import flash.events.Event;
  import flash.display.StageAlign;
  import flash.display.StageScaleMode;
  [SWF(width="500", height="500", frameRate="60")]
  public class Main extends Sprite{
  public function Main(){
  stage.align = StageAlign.TOP_LEFT;
  stage.scaleMode = StageScaleMode.NO_SCALE;
  addEventListener(Event.ADDED_TO_STAGE, init);
  private function init(event:Event):void{
  removeEventListener(Event.ADDED_TO_STAGE, init);
  trace(stage.stageWidth+" "+stage.stageHeight);
  var rectangle:Sprite = new Sprite();
  rectangle.graphics.beginFill(0xFF0000);
  rectangle.graphics.drawRect(0, 0, 1000, 1000);
  rectangle.graphics.endFill();
  this.addChild(rectangle);
  var rectangle2:Sprite = new Sprite();
  rectangle2.graphics.beginFill(0x0000FF);
  rectangle2.graphics.drawRect(0, 0, 500, 500);
  rectangle2.graphics.endFill();
  this.addChild(rectangle2);
I have this bug when I compile my swf with Flash Builder, I have the same bug with flash CC
stage.stageWidth, stage.stageHeight return 750 instead of 500
Thanks

Answer 1

Another people have this problem : https://bugbase.adobe.com/index.cfm?event=bug&id=3536168
Ark42 says "Flash works with HiDPI on Windows in Chrome and IE (PPAPI and ActiveX) but not in Firefox (NPAPI). Why does the NPAPI version not get the same fixes? Flash is basically completely unusable on Firefox if you have a 200% scaling setting in Windows, which is common on more and more laptops now."