avoid having to expand new principled node collapsed sections all the time.

to avoid having to open up the sections of the new principled node every time you want to connect to one of the hidden sockets, instead just drag from the output socket of the other node to anywhere on the principled node. This would then give you a list of input sockets to choose from (only showing the sockets of the collapsed area the mouse is over)

Otherwise we'll be continually opening and closing the collapsible panels on the principled nodes.