Been using the great qjackctl. I often have to work on multiple groups of ports, usually on the same device. I just found out that collapsing the device connections means "Disconnect" (think it is) disconnects ALL the connections between ports on that device. This is great but one thing that seems to be missing is selecting ports/connections using SHIFT/CTRL-Left Click (like you can do in file managers), and then being able to work on the selected ports/connections. This functionality may be there somewhere but I can't check because of lack of keyboard shortcut documentation. For example I just found out that hitting a letter on the keyboard alphabetically selects the relevant port name.