Consider highlighting hard/impossible chords

Your idea

It would be great if in addition to highlighting hard/impossible individual notes, MuseScore had at least some (possibly limited and instrument specific) ability to highlight hard/impossible chords.

Problem to be solved

MuseScore currently highlights individual notes that are hard to play for inexperienced players on a standard instrument in yellow, and notes that are impossible to play on standard instruments in red. But on chordal instruments, another playability consideration is how much hand contortion and stretching is needed to play the chord.

This is obviously hard to tell for an arbitrary instrument and an arbitrary chord, but there are some easy cases. For example, on standard piano keyboards more than 5 notes per hand is only possible through tricks and more than an octave of spread is going to be very hard for players who are less experienced or have smaller hands.

Given how many unplayable piano scores one can find on musescore.com, I think MuseScore would do the community a service by trying at least a bit to contribute to the education of inexperienced composer about this issue ;)

Prior art

Every music app I have ever used has this problem and does not try to solve it. The main reason why I think MuseScore should try to do so is that with musescore.com integration and branding, you are trying to "sell" a platform, not just composition software, and thus this is a concern that more directly impacts you.

One useful asset for implementing this would be a music composition book collecting hard patterns for various instruments. I'm not aware of any, but suspect some may exist, so it may be worth pinging composers with good bookshelves.

Additional context

The same arguments that apply against hard/impossible note detection also apply against hard/impossible chord detection:

• It will have false positives because the notion of hard/impossible chord is contextual to a certain performer and instrument. Exceptional performers and users of nonstandard instruments (e.g. a pianist with Rachmaninoff-sized hands, perfect motor skills and a narrow-keys keyboard) may have no issue with patterns that are impossible for other players.
• It will have lots and lots of false negatives because formulating an accurate model of playability is way beyond the reach of the MuseScore core devteam + contributors, which mean only easy cases of problematic chords can be detected. Much like today, in the melodic realm, MuseScore sees absolutely no issue with asking wind players to continuously play notes at the top of the range for an hour straight. These false negatives may give composers a false sense of security.

I believe MuseScore already accepted the tradeoff of having a hard pattern detection feature with false positives and negatives back when yellow and red notes were added. But at the time, this concern was mitigated by allowing composers to adjust the default warning range. For hard chords, such fine grained configuration might be be too complicated, and a score-wide on/off switch may be a better starting point.

The issue names no files, tests, or entry points; start by reviewing MuseScore’s existing individual-note playability highlighting. Narrow the work to a defined instrument and limited chord rules, then specify how warnings, false positives, configuration, and completion criteria should be validated.