MIDI preferences always come up empty on Mac+Windows
To reproduce, open the preferences dialog, switch to the MIDI tab and select some MIDI devices for input and output. Click Ok. The MIDI devices will work all right (even after exiting and relaunching purr-data, so the MIDI settings are properly recorded, too), but if you open the MIDI prefs again, it shows all MIDI devices as "None" again.
This is different from #203 (closed) in that it uses a different MIDI backend on Mac and Windows (probably portmidi, but I'm not sure). Also, the MIDI prefs always come up empty, even right after setting new devices.
It's also different from #92 (closed) (which apparently was fixed some time ago, so you might want to close it), since the MIDI settings do work all right, they're just not displayed when reopening the MIDI preferences.
Jonathan, do you have a clue what's going on there? Unfortunately, I have no way of debugging this myself, since I don't have portmidi as a backend option on Linux.