'Open' volta lines must be extended over the entire 'ending' to play back correctly
In a lengthy discussion about repeats and jumps which was provoked by some crashes and hangs in 2.0.1, it became apparent that MuseScore does not read 'open' volta lines for playback in the same way human musicians do. This behaviour has been verified for 2.0.3 (by Marc Sabatella). It was also mentioned in this multi-part issue from 2015.
Steps to reproduce:
1. Create a score with four repeats and a separate 'ending' for each.
2. Place a standard 'closed' volta over the first ending.
3. Place 'open' volta lines over the first measures of each of the 2nd, 3rd, and 4th endings.
3. Number the voltas sequentially.
4. Set 'repeat count' to '1' for all voltas.
5. Play back the score.
Expected result: MuseScore should play the repeats through in the order the voltas are numbered, jumping to the beginning of each volta in sequence after each repeat.
Actual result: MuseScore repeats each 'ending' after every repeat, and then jumps to the ends of the subsequent volta lines after that. (See this score: Les Baricades Mistérieuses 20161123 volta line bug.mscz )
To obtain proper playback, the user must extend volta lines to cover the entire 'ending' for each repeat. (See this score: Les Baricades rev 20161124.mscz )
Standard notation (for human musicians) does not require the volta line to cover the entire ending, only the first measure of it. MuseScore playback should recognise an 'open' volta line as taking effect at its anchor note/rest and continuing until the next repeat bar (or until the end of the piece, if there are no subsequent repeats).
Presently, the only way to produce correct playback order in complex scores is to extend the volta line as has been done in the second score posted above. This is obviously graphically unacceptable, and requires a complicated workaround that includes making the actual volta invisible, and inserting an 'inactive' (graphics-only) line with the 'volta number' tweaked into position using vertical and horizontal offsets in the Inspector.