I am trying to import a string sextet (2 violins, 2 violas, 2 cellos) in midi format into Notion. The viola parts in the original are in the alto clef. When imported, a mixture of clefs is inserted into the viola parts. Trying to change the clefs either to all alto or all treble doesn't work. Even if the file is saved, the different clefs recur. When importing the same midi file into another leading program, the original alto clef is kept throughout both viola parts.