在设计图像效果显示时，有些图像可能比较大，在窗口中不能完全显示出来。为了让用户能够浏览图像，可以单独设计一个滚动窗口，当控件放置在窗口中，用户可以通过滚动条来浏览控件的各个部分。-When designing graphics shows, some images may is bigger, cannot be fully displayed in the window. In order to enable users to browse images, can design a rolling window alone, when the control is placed in the window, the user can through the different parts of the scroll bar to view control.