anchor.diff:          '</table>' +
           '</div>'
           );
  -      var content = $('.diff-sheet', table);
  -      var numbers = $('.diff-line-numbers', table);
  +      const content = $('.diff-sheet', table);
  +      const numbers = $('.diff-line-numbers', table);
         content.html(diff.content);
         numbers.html(diff.line_numbers);
         cd.bindLineNumbersFromTo(content, numbers);
  
positive.code:     }
    };
  
    // - - - - - - - - - - - - - - - - - - - - - - - -
  
    var setupButton = function(name, handler) {
      $('#'+name+'-button-container').html('<button id="'+name+'-button" type="button"></button>');
      $('#'+name+'-button')
        .text(name)
  
negative.code:   // refresh [<] tag [>]
    //-----------------------------------------
  
    const refreshTagControls = () => {
      const colour = param.lights[param.nowTag - 1].colour;
      const minTag = 1;
      const maxTag = param.lights.length;
      const hasPrevTag = minTag < param.nowTag;
      const hasNextTag =          param.nowTag < maxTag;
  
      $('#now-tag-number')
        .removeClass()
  