On the object:
this.bounds = new go.Rect(0, 0, 637, 67);On the nodeTemplate:
{ width: 637, height: 67 }this properties are the same thing?
This number (637) is the size of the bigest description of a node.
I tried to make this.bounds (637) the size of each description in pixels, but this doesn’t solve my problem and increase a lot the time to render the diagram.