anchor.diff:            // TODO: Explore binding overlay to each of images (that jumps between them)
             var imgOverlay = new Overlay(imgSetEl.querySelector('img[data-compare-type=diff]'));
   
  +          // Save imgOverlay directly to imgSetEl
  +          imgSetEl.imgOverlay = imgOverlay;
  +
             // Append our element to the container element
             containerEl.appendChild(imgSetEl);
           });
  
positive.code:         this.overlayEl.style.height = height + 'px';
  
          // Emit an update event
          this.emitEvent('change:overlay', [evt, pointer, {
            absolute: {
              left: left,
              width: width,
  
negative.code:             top: top - this.bounds.top,
              height: height
            }
          };
          this.emitEvent('change:overlay', [evt, pointer, this.overlayInfo]);
        };
        Overlay.prototype.dragMove = function(evt, pointer, moveVector) {
          this.update(evt, pointer, moveVector);
  