As you will see, the gray box on the right will scroll until it reaches the top of the window, and then it will remain fixed until being pushed up by the footer.
I am looking to do a similar thing on my site with the navigation bar, but I’m not sure what this is called or how to do it!
@virtual sujiths777 was thanking you for providing the information, despite the fact he didn’t ask the original question. This would suggest that he found your post useful for a problem he had encountered.