JavaFX 2.0+ -- Menu显示超过一个屏幕滚动条Bug

//在菜单显示之后立刻校正滚动条位置
curMenu.setOnShown(new EventHandler<Event>() {
    private boolean firedBySelf = false;//用于标识是方案本身触发的刷新，还是外部操作触发的刷新

    @Override
    public void handle(Event t) {
        if (firedBySelf) {
            firedBySelf = false;
            return;
        }

　　　　　//找到最核心的显示皮肤类ContextMenuContent
        ContextMenu parentPopup = curMenu.getItems().get(0).getParentPopup();
        final Scene scene = parentPopup.getScene();
        Parent root = scene.getRoot();
        Group group = (Group) root.getChildrenUnmodifiable().get(0);
        ContextMenuContent content = (ContextMenuContent) group.getChildren().get(0);

        Class cla = ContextMenuContent.class;
        try {
　　　　　　　//通过反射修改滚动位置——私有变量ty
            Field field;
            field = cla.getDeclaredField("ty");
            field.setAccessible(true);
            field.set(content, 0);

　　　　　　　//刷新——隐藏再显示
            curMenu.hide();
            firedBySelf = true;
            curMenu.show();
        } catch (SecurityException ex) {
            log.error("", ex);
        } catch (IllegalArgumentException ex) {
            log.error("", ex);
        } catch (IllegalAccessException ex) {
            log.error("", ex);
        } catch (NoSuchFieldException ex) {
            log.error("", ex);
        }
    }
});