Every node can be identified by the value of its Key property. The Key value is unique not merely within a single Nodes collection but throughout the entire control. Use a key to retrieve a node from the control by calling the Item method of the Nodes collection.

If you attempt to insert a node with a key that already exists, or to change a key to an already existing value, a DuplicatedKey event is fired.

Nevertheless, if you are not interested in the key values, you may assign an empty string as key value to a node. This removes the node from the key map, but keeps the node itself within the control. All operations not involving a key may still be performed.

You can assign the empty string as Key value to as many nodes as desired.