Two-finger zoom in div containing Javascript affects stuff outside of it

I have a website that contains

<script type="text/javascript"> var data = null; var graph = null; google.load("visualization", "1"); google.setOnLoadCallback(drawVisualization); function drawVisualization() { data = new google.visualization.DataTable(); data.addColumn('number', 'x'); data.addColumn('number', 'y'); data.addColumn('number', 'z'); data.addRow([-1, 5, 3]); data.addRow([5, 3, 1]); data.addRow([1,2,1]) data.addRow([3, 1, 2]); data.addRow([-1, -2, 4]); data.addRow([4, -7, 4]); var options = { xMin: -3, yMin: -3, zMin: 0, xMax: 3, yMax: 3, zMax: 5, width: "300px", height: "300px", style: "vectors", showPerspective: false, showGrid: true, keepAspectRatio: true, verticalRatio: 1.0, zoomable: false }; graph = new links.Graph3d(document.getElementById('mygraph')); graph.draw(data, options); graph.setCameraPosition(0.4, undefined, undefined); } </script> <div id="mygraph"></div>

which essentially holds a 3d visualization using Google's graph3D. Everything works fine, except for an interference on a phone: When a used uses a two-finger zoom, any touching outside of the container still moves the thingy inside. And then a user cannot click on any link on the website anymore.

I know it is very vague, but can anyone point me to what could be an issue here? Basically I want to prevent that touching outside of the mygraph div does not interact with that visualization.

BTW the library code, if anyone wants to have a look, is here: https://matheistkeinarschloch.de/wp-content/uploads/2016/03/graph3D-1.js

Thanks so much for your help!