code: function (point) {
  			var series = this,
  				drillId = false,
  				nodeParent;
  			if ((point.node.parent !== series.rootNode) && (point.isLeaf)) {
  				nodeParent = point.node;
  				while (!drillId) {
  					nodeParent = series.nodeMap[nodeParent.parent];
  					if (nodeParent.parent === series.rootNode) {
  						drillId = nodeParent.id;
  					}
  				}
  			}
  			return drillId;
  		}
docs: Finds the drill id for a leaf node.
  Returns false if point should not have a click event
  @param {Object} point
  @return {string || boolean} Drill to id or false when point should not have a click event