anchor.diff:  
   
       mainChart.rows= await dailyValues(startDate.value,endDate.value,pair);
  +    mainChart.on['google-chart-select'].listen(sendMessage);
   
     }
   
  
positive.code:   }
    sendMessage(Event e)
    {
      window.alert(e.type);
    }
  
    loadChartDialog(Event e)
  
negative.code:     btnCharts =$['btnCharts'];
      startDate =$['startDate'];
      endDate =$['endDate'];
  
      selectPair.on['tap'].listen(loadChartDialog);
      btnCharts.on['tap'].listen(loadChart);
      loadCurrencyPairs();
  