amcharts Bubble with zoom

HTML

<script src="http://www.amcharts.com/lib/amcharts.js" type="text/javascript"></script>
<div id="chartdiv" style="width: 100%; height: 359px;"></div>

JavaScript

var chart;

var chartData = [{
    y: 10,
    x: 14,
    value: 59,
    y2: -5,
    x2: -3,
    value2: 44},
{
    y: 5,
    x: 3,
    value: 50,
    y2: -15,
    x2: -8,
    value2: 12},
{
    y: -10,
    x: -3,
    value: 19,
    y2: -4,
    x2: 6,
    value2: 35},
{
    y: -6,
    x: 5,
    value: 65,
    y2: -5,
    x2: -6,
    value2: 168},
{
    y: 15,
    x: -4,
    value: 92,
    y2: -10,
    x2: -8,
    value2: 102},
{
    y: 13,
    x: 1,
    value: 8,
    y2: -2,
    x2: -3,
    value2: 41},
{
    y: 1,
    x: 6,
    value: 35,
    y2: 0,
    x2: -3,
    value2: 16}];

AmCharts.ready(function() {
    // XY Chart
    chart = new AmCharts.AmXYChart();
    chart.pathToImages = "http://www.amcharts.com/lib/images/";
    chart.dataProvider = chartData;
    chart.marginRight = 0;
    chart.marginTop = 0;    
    chart.autoMarginOffset = 0;      
    chart.startDuration = 1.5;

    // AXES
    // X
    var xAxis = new AmCharts.ValueAxis();
    xAxis.position = "bottom";
    xAxis.axisAlpha = 0;
    xAxis.dashLength = 1;
    xAxis.minMaxMultiplayer = 1.2;
    xAxis.autoGridCount = true;
    chart.addValueAxis(xAxis);

    // Y
    var yAxis = new AmCharts.ValueAxis();
    yAxis.position = "left";
    yAxis.minMaxMultiplayer = 1.2;
    yAxis.axisAlpha = 0;
    yAxis.dashLength = 1;
    yAxis.autoGridCount = true;
    chart.addValueAxis(yAxis);

    // GRAPHS
    // first graph
    var graph = new AmCharts.AmGraph();
    graph.valueField = "value";
    graph.lineColor = "#b0de09";
    graph.xField = "x";
    graph.yField = "y";
    graph.lineAlpha = 0;
    graph.bullet = "bubble";
    chart.addGraph(graph);

    // second graph
    graph = new AmCharts.AmGraph();
    graph.valueField = "value2";
    graph.lineColor = "#fcd202";
    graph.xField = "x2";
    graph.yField = "y2";
    graph.lineAlpha = 0;
    graph.bullet = "bubble";
    chart.addGraph(graph);

    // CURSOR
    var chartCursor = new AmCharts.ChartCursor();
    chart.addChartCursor(chartCursor);

  ...