code: function setCategories(newCategories, doRedraw) {
  				// set the categories
  				axis.categories = userOptions.categories = categories = newCategories;
  
  				// force reindexing tooltips
  				each(associatedSeries, function (series) {
  					series.translate();
  					series.setTooltipPoints(true);
  				});
  
  
  				// optionally redraw
  				axis.isDirty = true;
  
  				if (pick(doRedraw, true)) {
  					chart.redraw();
  				}
  		}
docs: Set new axis categories and optionally redraw
  @param {Array} newCategories
  @param {Boolean} doRedraw