code: function () {
  		var series = this,
  			cursor = series.options.cursor,
  			css = cursor && { cursor: cursor },
  			graphic;
  
  		each(series.data, function (point) {
  			graphic = point.graphic;
  			if (graphic) { // doesn't exist for null points
  				graphic
  					.attr({ isTracker: true })
  					.on('mouseover', function () {
  						series.onMouseOver();
  						point.onMouseOver();
  					})
  					.on('mouseout', function () {
  						if (!series.options.stickyTracking) {
  							series.onMouseOut();
  						}
  					})
  					.css(css);
  			}
  		});
  
  	}
docs: Create individual tracker elements for each point
   drawTracker: ColumnSeries.prototype.drawTracker,