anchor.diff:      let html = '';
       let wasIndex = 0;
       $.each(param.events, (_n, event) => {
  -      const colour = event.colour;
  -      if (colour !== '') {
  -        const nowIndex = event.index;
  -        const barOrGap = (param.nowIndex === nowIndex) ? 'bar' : 'gap';
  -        html += makeTrafficLightHtml(colour, wasIndex, nowIndex, barOrGap);
  -        wasIndex = nowIndex;
  +      if (event.colour !== '') {
  +        html += makeTrafficLightHtml(wasIndex, event);
  +        wasIndex = event.index;
         }
       });
       return html;
  
positive.code:   };
  
    //-----------------------------------------
    // refresh traffic-light navigator
    //    [<]index[>] traffic-lights...
    //-----------------------------------------
  
    const refreshIndexNavigator = () => {
  
negative.code:   };
  
    //-----------------------------------------
    // [<]avatar[>]
    //-----------------------------------------
  
    const refreshAvatarNavigator = () => {
  