Instruments can not get muted in mixer independently in score and parts

[Jojo-Schmitz]

Issue type

General playback bug

Bug description

No response

Steps to reproduce

In a score (e.g. closed score SATB + Piano) with parts (for Choir, i.e. Men and Women) chord symbols (above the Womens staff) mute them in the main score (as there is a full piano they'd otherwise collide with).
Now in the part (for Choir) they are muted too, but would be valuable for (self-)rehearsal.
If you unmute them in the part, they unmute in the main score too, which then collides with the piano notes.

Screenshots/Screen recordings

No response

MuseScore Version

4.2.0

Regression

Yes, this used to work in MuseScore 3.x and now is broken

Operating system

Windows 11

Additional context

See also #18092
For me this is one of several issues that prevent me from switching from Mu3 to Mu4

[bkunda]

This is a known issue and has been raised here in this PR. We aim to address it when the PR gets picked up again by @mathesoncalum.

[Jojo-Schmitz]

The isxsue #19235 is a different thing, it is about the option to mute or unmute hidden instruments. But your comment in #19433 is to the pount indeed.