this.initMask = function () {
        this.mask = new Sprite();
        this.mask.width = this.width;
        this.mask.height = this.height;
        this.mask.scrollRect = new Rectangle();
        this.mask.scrollRect.setTo(0, 0, this.width, this.height);
        this.mask.optimizeScrollRect = true;
        this.addChild(this.mask);
    }
    this.initContent = function () {
        this.content = new Box();
        this.content.width = this.width;
        this.content.autoSize = true;
        this.content.y = this.scrollMode == DOWN_TO_TOP ? this.height : 1;
        this.mask.addChild(this.content);

        this.content.on(Event.MOUSE_DOWN, this, this.onMouseDown);
        this.content.on(Event.MOUSE_WHEEL, this, this.onMousewheel);
    }
    this.createText = function (_content, _fontSize, _color, _width, _autoSize, _wordWrap, _ID) {
        var txt = new Text();
        txt.text = _content;
        txt.cacheAs = 'bitmap';
        txt.fontSize = _fontSize;
        txt.bold = true;
        txt.font = 'wordFont';
        txt.color = _color;
        txt.strokeColor = '#000000';
        //txt.stroke = 2;
        txt.width = _width;
        txt.autoSize = _autoSize;
        txt.wordWrap = _wordWrap;
        txt.ID = _ID === undefined ? 0 : _ID;
        this.content.addChild(txt);
        return txt;
    }

this.mask.optimizeScrollRect = true;

this.content.y = 0 的情况下将不会显示内容 this.content.y = 1就显示正常了

this.mask.optimizeScrollRect = false;
this.content.y = 0 也会正常显示

开发的时候不知道是哪个版本是正常的现在1.5.3版本出问题了不知道是哪个版本改动出了问题