The node template uses a custom Part.selectionAdornmentTemplate to add a row of Buttons when the node is selected. Select a node and you will see the Buttons for the node.
The first button, "T", when clicked, starts in-place editing of the text.
The second button, "C", when clicked, changes the color of the node, rotating through a list of colors.
The third button, "L", when clicked or dragged, starts the LinkingTool, drawing a new link starting at the selected node.
The fourth button, "N", when clicked, adds a new node and creates a link from the selected node to the new node. Dragging from the fourth button does the same thing as a click but also activates the DraggingTool, allowing the user to drag the new node where they like.