Vertically scroll the left(Navigation) and the center column(Page content) independently

For a loaded Wiki it would be very helpful if the left column (with the Navigation panel) scrolls independently from the center column (with the page content). If you click on a Navigation entry close to the bottom of the page, this opens a new page, and with this, the bottom part of the left column including the clicked entry will disappear. With a large tree of pages and working on a set of neighbored sub-sub-pages, you now always have to scroll down again to the relevant part of the Navigation.