Highlight the given series item.
@param {Object} item Info about the item; same format as returned by #getItemForPoint.
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);
        }
    }