If I'm looking at a Midi file in the File browser, they can be expanded to show the parts.
Some midi files also let you drag one part into your current open song to a track, or even drag into the Tempo bar to import the tempo map.
Other midi files will only open a completely new song when you drag a part over to the current song, creating a second song.
My Question: Does anyone know what the difference is in the Midi files, and if I can force one that isn't allowing drag and drop of individual parts to do so?