Yes, I was able to reproduce the same problem through trail and errors.
I removed the layout from go.Diagram
myDiagram =
$(go.Diagram, "myDiagramDiv", // must name or refer to the DIV HTML element
{
initialAutoScale: go.Diagram.Uniform, // an initial automatic zoom-to-fit
contentAlignment: go.Spot.Center, // align document to the center of the viewport
"undoManager.isEnabled": true
});
and removed all tokens and only kept the green one
myDiagram.model.addNodeDataCollection([
{ category: "token", at: 1, color: "green" },
]);
and removed one node and all its links
var nodeDataArray = [
{ key: 1, text: "Concept Maps" },
{ key: 2, text: "Organized Knowledge" },
{ key: 3, text: "Context Dependent" },
{ key: 4, text: "Concepts" },
{ key: 5, text: "Propositions" },
{ key: 6, text: "Associated Feelings or Affect" },
{ key: 7, text: "Perceived Regularities" },
{ key: 8, text: "Labeled" },
{ key: 9, text: "Hierarchically Structured" },
{ key: 10, text: "Effective Teaching" },
{ key: 11, text: "Crosslinks" },
{ key: 12, text: "Effective Learning" },
{ key: 13, text: "Events (Happenings)" },
{ key: 14, text: "Objects (Things)" },
{ key: 15, text: "Symbols" },
{ key: 16, text: "Words" },
{ key: 17, text: "Creativity" },
{ key: 18, text: "Interrelationships" },
{ key: 19, text: "Infants" },
];
var linkDataArray = [
{ from: 1, to: 2, text: "represent" },
{ from: 2, to: 3, text: "is" },
{ from: 2, to: 4, text: "is" },
{ from: 2, to: 5, text: "is" },
{ from: 2, to: 6, text: "includes" },
{ from: 2, to: 10, text: "necessary\nfor" },
{ from: 2, to: 12, text: "necessary\nfor" },
{ from: 4, to: 5, text: "combine\nto form" },
{ from: 4, to: 6, text: "include" },
{ from: 4, to: 7, text: "are" },
{ from: 4, to: 8, text: "are" },
{ from: 4, to: 9, text: "are" },
{ from: 5, to: 9, text: "are" },
{ from: 5, to: 11, text: "may be" },
{ from: 7, to: 13, text: "in" },
{ from: 7, to: 14, text: "in" },
{ from: 7, to: 19, text: "begin\nwith" },
{ from: 8, to: 15, text: "with" },
{ from: 8, to: 16, text: "with" },
{ from: 9, to: 17, text: "aids" },
{ from: 11, to: 18, text: "show" },
{ from: 12, to: 19, text: "begins\nwith" },
{ from: 17, to: 18, text: "needed\nto see" },
];
Can you try this configuration and check. If not try removing more nodes.