Measure numbers of pickup measure can desync between parts

Issue type

UX/Interaction bug (incorrect behaviour)

Description with steps to reproduce

Normally, all measure properties sync between the score and parts, including whether it's included in the measure count or adds to the measure count. But this is not true for the pickup measure, if the pickup measure was newly created with at least one part open.

To reproduce:

1. Open all parts.
2. With all parts open, insert a new measure at the beginning of the score.
3. Make it a pickup measure by right-clicking on it, selecting "Measure properties...", then decreasing the value of the actual duration.
4. Choose a part, then right-click on the pickup measure and select "Measure properties..."
5. Toggle "Exclude from measure count" or add a nonzero value to "Add to measure number".
6. Observe the changed measure numbers of all the other measures. (It is recommended to change the style so that measure numbers display on every measure.)
7. Go to another part and observe its measure numbers.

Expected behavior: The updated measure numbers are consistent across every part.
Actual behavior: The measure numbers are updated only in the part where you changed it, resulting in a desync of measure numbers across parts.

Supporting files, videos and screenshots

Here is an MSCZ that demonstrates the issue. Screenshots are also attached.

In this MSCZ, there are three parts: score, piano, and violin.

• In the score, the pickup measure is not excluded from the count. The last measure is numbered 9.
• In the piano part, the pickup measure is excluded from the count. The last measure is numbered 8.
• In the violin part, the pickup measure is not excluded from the count, and it adds a value of 1 to the count. The last measure is numbered 10.

measurenumberdesync.zip

Score:

Piano part:

Violin part:

Video recording: https://github.com/musescore/MuseScore/issues/32713#issuecomment-4182613717

In which versions of MuseScore Studio is this issue present?

4.6.5

Regression

I was unable to check

Operating system

Windows 11

Additional context

No response

Checklist

• This report follows the guidelines for reporting bugs and issues
• I have verified that this issue has not been logged before, by searching the issue tracker for similar issues
• I have attached all requested files and information to this report
• I have attempted to identify the root problem as concisely as possible, and have used minimal reproducible examples where possible

Reproduce the desynchronization using the attached measurenumberdesync.zip and the listed steps, then trace how Measure properties changes propagate between the score and parts. Done means pickup-measure counting and numbering remain consistent across every part after toggling exclusion or adding to the measure number.