A graphical user interface system that visually represents a graph node having multiple input ports, and that automatically adjusts the number of input ports to the graph node as open input ports are connected to upstream graph node(s) and/or as used input ports are disconnected from upstream graph node(s). Upon detecting that a set of one or more input ports has just been connected to one or more upstream graph nodes, the system may automatically add one or more additional input ports to the visual representation of the graph node without explicit user instruction. Upon detecting that a set of one or more of the input ports has just been disconnected from one or more upstream graph nodes, the system may automatically remove the determined one or more input ports from the visual representation of the graph node.