I know you can set a node socket's fill color to anything color, but can you also set the stroke color to any color too so that the socket is completely invisible?
The need for this feature is really prompted my need to use a "dummy" sockets to insert spacing between other sockets in a node in order to separate input sockets visually in a group of inputs belonging to a set. (see attachment). My node makes sure this dummy socket cannot be linked to other nodes, but it would be nice if I could make the socket nodule be completely transparent not just the fill. (in the attachment you can see the separator sockets show the outline of the socket nodule).
Note: of course if the node API would allow inserting separators between sockets such feature to make the nodule 100% transparent would not be of use in this case.