In the sample - the links go all the way to the nodes:
but when running (in chrome) the links only make it to the group:
How do you change the behaviour to be that of the first image?
Ah, yes, we did not update the screenshot when we modified the sample.
Just change your node template to use go.Node instead of the TreeNode class, which you can delete. And do the same with the MappingLink class – replace the reference in the link template with go.Link.