set = $('.sphinxsidebar').position()['top'];
        var wintop = win.scrollTop();
        var winbot = wintop + win.innerHeight();
        var curtop = sb.position()['top'];
        var curbot = curtop + sbh;
        // does sidebar fit in window?
        if (sbh < win.innerHeight()) {
          // yes: easy case -- always keep at the top
          sb.css('top', $u.min([$u.max([0, wintop - offset - 10]),
                                $(document).height() - sbh - 200]));
        } else {
          // no: 