1) User is reading some post X, on a page.
2) User clicks the in-page navigation Up arrow, and browser slides to the cited post.
3) User can click the Back button, and return to the post he was viewing in step1.
Step3 is where it currently fails.
To forestall objections, this is not a frivolous request, because we're trying to improve on VB's post-citation system, and there the browser may not slide up in a graceful fashion, but it is always possible to return to the original post by pressing Back, after viewing the cited post.