Stock events on multiple dataset stock chart

by amcharts

HTML

<script type="text/javascript" src="http://www.amcharts.com/lib/3/amcharts.js"></script>
<script type="text/javascript" src="http://www.amcharts.com/lib/3/serial.js"></script>
<script type="text/javascript" src="http://www.amcharts.com/lib/3/themes/none.js"></script>
<script type="text/javascript" src="http://www.amcharts.com/lib/3/amstock.js"></script>
<div id="chartdiv"></div>

CSS

body {
    font-family: Verdana;
    font-size: 12px;
    padding: 10px;
}

#chartdiv {
	width	: 100%;
	height	: 500px;
}

JavaScript

var chartData1 = [];
var chartData2 = [];
var chartData3 = [];
var chartData4 = [];

generateChartData();

function generateChartData() {
	var firstDate = new Date();
	firstDate.setDate(firstDate.getDate() - 500);
	firstDate.setHours(0, 0, 0, 0);

	for (var i = 0; i < 500; i++) {
		var newDate = new Date(firstDate);
		newDate.setDate(newDate.getDate() + i);

		var a1 = Math.round(Math.random() * (40 + i)) + 100 + i;
		var b1 = Math.round(Math.random() * (1000 + i)) + 500 + i * 2;

		var a2 = Math.round(Math.random() * (100 + i)) + 200 + i;
		var b2 = Math.round(Math.random() * (1000 + i)) + 600 + i * 2;

		var a3 = Math.round(Math.random() * (100 + i)) + 200;
		var b3 = Math.round(Math.random() * (1000 + i)) + 600 + i * 2;

		var a4 = Math.round(Math.random() * (100 + i)) + 200 + i;
		var b4 = Math.round(Math.random() * (100 + i)) + 600 + i;

		chartData1.push({
			date: newDate,
			value: a1,
			volume: b1
		});
		chartData2.push({
			date: newDate,
			value: a2,
			volume: b2
		});
		chartData3.push({
			date: newDate,
			value: a3,
			volume: b3
		});
		chartData4.push({
			date: newDate,
			value: a4,
			volume: b4
		});
	}
}

var stockEvents = [{
			date: chartData1[490].date,
			type: "sign",
			backgroundColor: "#85CDE6",
			graph: "g1",
			text: "S",
			description: "This is description of an event"
		}, {
			date: chartData1[460].date,
			type: "flag",
			backgroundColor: "#FFFFFF",
			backgroundAlpha: 0.5,
			graph: "g1",
			text: "F",
			description: "Some longerntext can alson be added"
		}, {
			date: chartData1[430].date,
			showOnAxis: true,
			backgroundColor: "#85CDE6",
			type: "pin",
			text: "X",
			graph: "g1",
			description: "This is description of an event"
		}, {
			date: chartData1[400].date,
			showOnAxis: true,
			backgroundColor: "#85CDE6",
			type: "pin",
			text: "Z",
			graph: "g1",
			description: "This is description of an event"
		}, {
			date: chartData1[370].date,
			type: "sign",
			backgroundColor: "#85CDE6",
			graph:...