anchor.diff:      var diffFileDiv = function(filename) { return id(filename + '_diff_div'); };
   
       var loadFrom = function(diff) {
  -
         var id = diff.id;
  -      var filenameNode = $('#radio_' + id); // clash with kata-page filename when in dialog?
  +      var filenameNode = $('#radio_' + id);
         var filename = getFilename(filenameNode);
         var sectionCount = diff.section_count;
         var diffSheet = diffFileContentFor(filename);
  
positive.code:     }; // loadFrom()
  
      $.each(diffs, function(_n, diff) {
        var filename = $('#radio_' + diff.id); // clash with kata-page filename when in dialog?
        filename.click(loadFrom(diff));
      });
    }; // buildDiffFilenameHandlers()
  
negative.code:   // - - - - - - - - - - - - - - - - - - - - - - - -
  
    var buildDiffFilenameHandlers = function(diffs) {
      // Builds click handlers for all filenames for a given
      // [ kata-id, animal-name, was-tag, now-tag] tuple.
      // When you open a new filename it auto-scrolls its first diff-chunk.
      // When you reclick a filename it auto-scrolls to its *next* diff-chunk.
      var previousFilenameNode;
      var alreadyOpened = [];
      var getFilename = function(node) { return $.trim(node.text()); };
  