The provided "patch" adds the possibility for predefing a clef for each available instrument.
The clef will be automatically applied when changing the instrument. For that I added a checkbox in the track properties to influence this behaviour. Until now the clef is only predefined for some instruments I am comfortable with :). If no clef is predefined, to sopran clef is used automatically.
The translation needed for the checkbox are also integrated in the patch (DE and EN).