I’d like to see (or more precisely, i really need it) some indication of whether or not Cantabile can actually find the source or target of a route – an indicator of whether there is something there on the port. This would be very handy in tracking down the question of why am i getting no response from playing keys on this keyboard – which could be that the keyboard is in some other mode, or that Windows has gone and renumbered all my USB ports, or i’ve got a bad USB cable, or etc etc.
What i ususally end up doing (my go-to procedure) is to go into Options | MIDI ports | Add, and see whether or not the device in question appears in the list of available devices. It’s obvious from this that Cantabile knows what devices it sees, so it should be straightforward to indicate to the user, without us having to go looking.
I would suggest using the indicator LED’s on the MIDI route slot, which would change color to indicate a failed connection: