Measure number appears after edit in first measure after section break with intervening frame
I suspect I broke this while fixing some similar issues recent, see https://github.com/musescore/MuseScore/pull/7026
1) load attached file
2) select the middle C in the second measure of the section section
3) press any arrow key or make any other edit to that measure
Result: measure number (5) appears above the first measure of the section, despite the fact that first measures of a section should have this suppressed.
It corrects itself on save/reload, or on any edit to that first measure, or to the intervening frame, or any operation that triggers a full relayout.
I assume the cause is wrapped up in how we do partial relayout, trying to figure out an appropriate first and last measure to layout and processing only those. Somehow in reprocessing this system, we aren't correctly doing the look-behind I had added in that PR.
It's possible also the cause for this is wrapped up in other changes made as part of the staff justification algorithm, since that affected this determination. Or just wires got crossed between the two sets of changes.