Activating the node title editor using just the mouse:
(1) Click a node to select it, wait a moment, then click it again.
- or -
Right-click a node, then click Edit Node Name.
(2) The node's name becomes an edit box.
(3) Type a new name or edit the existing name.
(4) Press "Enter" to apply the changes (you can also press the "Esc" key to cancel the changes).