Voltas (and other lines) disappear upon entering notes
Ubuntu Studio 14.04, GIT commit: e176e25
1) new score
2) add volta to bar 2
3) bar 1, note entry
4) start entering quarter notes
Result: volta disappears as soon as you enter a note into measure 2
The same is true for other lines. Realistically, it makes sense for slurs and maybe some other types of lines that you think of as being attached to individual notes that they would be deleted when the notes are replaced. But it doesn't make sense for voltas, pedal lines, or ottavas.
I am guessing this is a side effect of the fix for #28761: Lengthening note before a line produces incorrect results. Replacing the start note of a spanner needs to be treated differently than extending the previous note.