code: function () {
  		var series = this,
  			chart = series.chart,
  			renderer = chart.renderer,
  			shapeArgs,
  			tracker,
  			trackerLabel = +new Date(),
  			options = series.options,
  			cursor = options.cursor,
  			css = cursor && { cursor: cursor },
  			rel;
  
  		each(series.data, function (point) {
  			tracker = point.tracker;
  			shapeArgs = point.trackerArgs || point.shapeArgs;
  			delete shapeArgs.strokeWidth;
  			if (point.y !== null) {
  				if (tracker) {// update
  					tracker.attr(shapeArgs);
  
  				} else {
  					point.tracker =
  						renderer[point.shapeType](shapeArgs)
  						.attr({
  							isTracker: trackerLabel,
  							fill: TRACKER_FILL,
  							visibility: series.visible ? VISIBLE : HIDDEN,
  							zIndex: options.zIndex || 1
  						})
  						.on(hasTouch ? 'touchstart' : 'mouseover', function (event) {
  							rel = event.relatedTarget || event.fromElement;
  							if (chart.hoverSeries !== series && attr(rel, 'isTracker') !== trackerLabel) {
  								series.onMouseOver();
  							}
  							point.onMouseOver();
  
  						})
  						.on('mouseout', function (event) {
  							if (!options.stickyTracking) {
  								rel = event.relatedTarget || event.toElement;
  								if (attr(rel, 'isTracker') !== trackerLabel) {
  									series.onMouseOut();
  								}
  							}
  						})
  						.css(css)
  						.add(point.group || chart.trackerGroup); // pies have point group - see issue #118
  				}
  			}
  		});
  	}
docs: Draw the individual tracker elements.
  This method is inherited by scatter and pie charts too.