Apple Shake 4 New Features - Manual (Page 21)

Chapter 1 Shake 4.0 Interface Enhancements 21
2 Move the pointer over the second node you want to connect so that the knot is visible,
then Shift-click the knot to connect both nodes together.
You can also use this technique to connect a group of nodes to a single multi-input
node, such as the MultiLayer, MultiPlane, or Select node.
To connect several nodes to a multi-input node at once:
1 Select all of the nodes you want to connect to the multi-input node.