code: function(config) {
          var me = this,
              surface,
              sprites,
              tipSurface;
          if (config.tips) {
              me.tipTimeout = null;
              me.tipConfig = Ext.apply({}, config.tips, {
                  renderer: Ext.emptyFn,
                  constrainPosition: true,
                  autoHide: true
              });
              me.tooltip = new Ext.tip.ToolTip(me.tipConfig);
              me.chart.surface.on('mousemove', me.tooltip.onMouseMove, me.tooltip);
              me.chart.surface.on('mouseleave', function() {
                  me.hideTip();
              });
              if (me.tipConfig.surface) {
                  //initialize a surface
                  surface = me.tipConfig.surface;
                  sprites = surface.sprites;
                  tipSurface = new Ext.chart.TipSurface({
                      id: 'tipSurfaceComponent',
                      sprites: sprites
                  });
                  if (surface.width && surface.height) {
                      tipSurface.setSize(surface.width, surface.height);
                  }
                  me.tooltip.add(tipSurface);
                  me.spriteTip = tipSurface;
              }
          }
      }
docs: /* End Definitions