GOJS - Event Listener

HTML

<script src="http://www.gojs.net/latest/release/go.js"></script>
<div id="myDiagram"></div>

CSS

#myDiagram{
    width:200px;
    height:200px;
}

JavaScript

var $ = go.GraphObject.make;
var myDiagram = $(go.Diagram, "myDiagram", {
    initialContentAlignment: go.Spot.Center,
    "undoManager.isEnabled": true
});

myDiagram.addDiagramListener("ObjectDoubleClicked", function (ev) {
    alert(ev.subject);
    console.log(ev.subject);
    console.log(ev.subject.ie);
});

myDiagram.nodeTemplate = $(go.Node, "Auto",
$(go.Shape, "RoundedRectangle",
new go.Binding("fill", "color")),
$(go.TextBlock, {
    margin: 3
},
new go.Binding("text", "key")));
myDiagram.model = new go.GraphLinksModel(
[{
    key: "Alpha",
    color: "lightblue"
}, {
    key: "Beta",
    color: "orange"
}, {
    key: "Gamma",
    color: "lightgreen"
}, {
    key: "Delta",
    color: "pink"
}], [{
    from: "Alpha",
    to: "Beta"
}, {
    from: "Alpha",
    to: "Gamma"
}, {
    from: "Beta",
    to: "Beta"
}, {
    from: "Gamma",
    to: "Delta"
}, {
    from: "Delta",
    to: "Alpha"
}]);