What is root?

Imagine you want to add a new node before the created node and connect before the initial node.

(as shown in the picture)

If you press "Save Version", it will give an error node with uuid XXXXX is orphan.

IT is because the system considers the first node as an initial one, and any other nodes which are prior the initial node will be considered as an orphan.

In order to avoid this error, you should make that first node as ROOT.

And hit "Save Version".