It does work if you have the scrollbar on the right, I have it on the left. Anyways after trying it with the scrollbar on the right It could get improved if hovering over the zone of the scrollbar activate it because when you need to scroll to a very exact zone on the page, as when you want to see a video and want to focus only on it I found it difficult to do it if it is not clicking directly on the sidebar. Good idea, though.