The list of available definition files for the selected MIDI Target is not updated when you click on a different target. It always shows the Roland SC-55...
Unlike for the plug-ins, the CopperPlug has no idea of what is behind the MIDI port. A VST plug-in can be identified by its filename, the description given by the plug-in itself... But a MIDI Out can't give back any information.
But indeed the list title is not correct. I change it to "Available definition files for MIDI Target" (removed the "selected" word).
What about using the System Exclusive IDentity Request to identify the connected device (if it answers the request)? You could save the ID string in the definition file as it's done by this program: http://de.virtualdj.com/wiki/Controller ... ation.html