This is a minibrowser/scroll bar.
Try scrolling by using the buttons.
This article has been encased in a minibrowser for educational use.
Minibrowsers are div style windows for browsing.
How to make one Edit
First, add <div style="width:(percent here); height:(xxx pixels); padding:10px; overflow:scroll; border:1px solid #000;">, then add your content, then close it with a </div>, and you're done!
See also Edit