Crash on inserting measure repeat in score with parts & mmrests

Windows 7, GIT commit: 2b832e8

1) new score for two instruments, 32 bars
2) add notes to top part, first measure
3) generate parts
4) drag measure repeat to bar 2

Result: crash

Crash occurs only if doing this after parts are generated, and only if the bar to which you drag the repeat is part of an mmrest in the part. For example, if you after step 3 you add notes to bar 3, then drag the repeat to measure 2, it works as expected.