Merge "fix sidebar autoscroll when the selected doc is not visible. bug: 9676913" into jb-mr2-docs

  if ($nav.is(':visible')) {

    var $selected = $(".selected", $nav);

    if ($selected.length == 0) return;

    if ($selected.length == 0) {

      // If no selected item found, exit

      return;

    }

    var selectedOffset = $selected.offset().top; // measure offset from top, relative to entire page

    if (selectedOffset > $nav.height() * .8) { // multiply nav height by .8 so we move up any

                                               // items more than 80% down the nav

      // scroll the item up by an amount 125px less than the window height (account for site header)

      // and then multiply nav height by .8 to match the 80% threshold used above

      api.scrollTo(0, selectedOffset - 125 - ($nav.height() * .8), false);

    var selectedOffset = $selected.position().top;

    if (selectedOffset + 90 > $nav.height()) {  // add 90 so that we scroll up even 

                                                // if the current item is close to the bottom

      api.scrollTo(0, selectedOffset - ($nav.height() / 4), false); // scroll the item into view

                                                              // to be 1/4 of the way from the top

    }

  }

}