GoTreeLayout artificial nodes

I would like to ask about artificial nodes in TreeLayout.

I was trying to add an artificial (having GoObject set to null) node connected with other nodes. Unfortunetly I was getting null reference exception inside the performlayout method.
Does anyone know how to user artifical nodes ?
I'd be very grateful for any sugestions.

Yes, that’s a bug in GoLayoutTree.AddComments, not checking for GoLayoutTreeNode.GoObject being null.

If you don't have any GoBalloons in your diagram pointing at nodes that you are laying out, it's easiest to just override that method to be a no-op:
[code] protected override void AddComments(GoLayoutTreeNode n) {}[/code]