Bug scale on Mozilla Firefox Windows 8.1

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