This feature allows to manipulate vehicle’s nodes using the cursor. This makes it possible to:
While grabbing a node, use Mouse Wheel Up/Down to adjust the strength of the grab. The strength is displayed on the on-screen label.
While grabbing a node, press the Middle Mouse Button to pin a node.
While grabbing a node, hover over another node and press the Middle Mouse Button when the label indicates so via a change of color (see visual example below). To detach two nodes that were previously attached, simply middle-click on one of the attached nodes.