Copy-paste a multimeasure rest on another one causes corruption after undo
GIT commit ca4d9e9 / Windows7
1) Load this file: new test corruption.mscz
2) Generate parts (new all -> Ok)
3) View part
4) Range selection of the first MM rest (including the whole note, or not: same issue)
5) Copy-paste into the second MM rest
6) Undo -> press "M"