Steps to reproduce:
1) Create a new score with one instrument (or use the treble clef template)
2) Insert a vertical frame on measure number 2, such that one measure is present before the frame
3) Select the 4/4 time signature and press "delete"
=> Crash
Comments
Got it - it's code I added to reinstate the time signature after the frame, except there is no time signature to reinstate.
https://github.com/musescore/MuseScore/pull/1976
The problem was with my code, and I feel I understand the cause of the crash and the fix pretty well.
Fixed in 687886e9d2
Automatically closed -- issue fixed for 2 weeks with no activity.