code: function(item) {
          if (!item) {
              return;
          }
          
          var me = this,
              sprite = item.sprite,
              opts = Ext.merge({}, me.highlightCfg, me.highlight),
              surface = me.chart.surface,
              animate = me.chart.animate,
              p, from, to, pi;
  
          if (!me.highlight || !sprite || sprite._highlighted) {
              return;
          }
          if (sprite._anim) {
              sprite._anim.paused = true;
          }
          sprite._highlighted = true;
          if (!sprite._defaults) {
              sprite._defaults = Ext.apply({}, sprite.attr);
              from = {};
              to = {};
              // TODO: Clean up code below.
              for (p in opts) {
                  if (! (p in sprite._defaults)) {
                      sprite._defaults[p] = surface.availableAttrs[p];
                  }
                  from[p] = sprite._defaults[p];
                  to[p] = opts[p];
                  if (Ext.isObject(opts[p])) {
                      from[p] = {};
                      to[p] = {};
                      Ext.apply(sprite._defaults[p], sprite.attr[p]);
                      Ext.apply(from[p], sprite._defaults[p]);
                      for (pi in sprite._defaults[p]) {
                          if (! (pi in opts[p])) {
                              to[p][pi] = from[p][pi];
                          } else {
                              to[p][pi] = opts[p][pi];
                          }
                      }
                      for (pi in opts[p]) {
                          if (! (pi in to[p])) {
                              to[p][pi] = opts[p][pi];
                          }
                      }
                  }
              }
              sprite._from = from;
              sprite._to = to;
              sprite._endStyle = to;
          }
          if (animate) {
              sprite._anim = new Ext.fx.Anim({
                  target: sprite,
                  from: sprite._from,
                  to: sprite._to,
                  duration: 150
              });
          } else {
              sprite.setAttributes(sprite._to, true);
          }
      }
docs: Highlight the given series item.
  @param {Object} item Info about the item; same format as returned by #getItemForPoint.