Yes it does. Try moving the nodes around to increase the size of the documentBounds, and then scroll a scrollbar.
<!DOCTYPE html>
<html>
<head>
<title>Minimal GoJS Sample</title>
<!-- Copyright 1998-2022 by Northwoods Software Corporation. -->
</head>
<body>
<div id="myDiagramDiv" style="border: solid 1px black; width:100%; height:600px"></div>
<script src="https://unpkg.com/gojs"></script>
<script id="code">
const $ = go.GraphObject.make;
const myDiagram =
$(go.Diagram, "myDiagramDiv",
{
"ViewportBoundsChanged": e => console.log(e.diagram.viewportBounds.toString(), Date.now()),
"animationManager.isInitial": false,
"undoManager.isEnabled": true
});
myDiagram.nodeTemplate =
$(go.Node, "Auto",
$(go.Shape,
{ fill: "white" },
new go.Binding("fill", "color")),
$(go.TextBlock,
{ margin: 8 },
new go.Binding("text"))
);
myDiagram.model = new go.GraphLinksModel(
[
{ key: 1, text: "Alpha", color: "lightblue" },
{ key: 2, text: "Beta", color: "orange" },
{ key: 3, text: "Gamma", color: "lightgreen" },
{ key: 4, text: "Delta", color: "pink" }
]);
</script>
</body>
</html>