Haxe bug (HTML5/Javascript target)

gistfile1.hx

package test;

import flash.display.BitmapData;
import flash.display.Bitmap;
import flash.display.Sprite;
import flash.events.Event;

class Main extends Sprite {

    private var _bitmaps:Array<Dynamic>;
    public function new () {
        super ();

        _bitmaps = new Array<Dynamic>();

        for (i in 0...100) {
            var bitmapData:BitmapData = new BitmapData(40, 40, false, Std.int (Math.random () * 0xFFFFFF));
            var bitmap:Bitmap = new Bitmap(bitmapData);
            bitmap.x = Math.random()*640;
            bitmap.y = Math.random()*480;
            addChild(bitmap);
            _bitmaps.push(bitmap);
        }
        stage.addEventListener(Event.ENTER_FRAME, onEnterframe);
        trace(_bitmaps[0]);

    }

    private function onEnterframe(event:Event):Void {
        for (i in 0..._bitmaps.length) {
            cast(_bitmaps[i], Bitmap).x++;
            _bitmaps[i].nmeY++;
        }
    }

}