Support for Custom Key signature transposing - diatonically, without keeping degree alterations.

Hi, Musescore.

I'm writing etudes in harmonic minor, harmonic major, melodic minor etc. (scales that'd end up with accidentals on traditional key sigs) using custom key signatures. (This I find better displays the alteration in comparison to traditional keys.)

This not only clearly demonstrates alteration in the altered keys ('raised' or 'major' 7th in this case), and also makes the input process many folds quicker.

Then I found out that copying and pasting the initial arpeggio to a new key and diatonically transposing it up and back down without keeping degree alterations - isn't supported for the custom key signatures. This would save a lot of time while working with etudes with custom key signatures.

Now that the playback supports custom key signatures, how about transposing support for custom key signatures? :D

Thank you again, Musescore 4 really is the best thing since sliced notation app bread!