multi-bar rest not working properly inside repeated section with volta

I created a short piece, attached, that has a 4-bar repeated section with a first and second ending. The first time through, all 4 bars are tacet. The second time through, the first three bars are tacet, but in the last bar (the second ending) there is a three-beat rest followed by a quarter note, and then more music in subsequent measures. The page looks fine until I select "create multi-bar rests" from Edit General Style. With multi-bar rests on, what I should get is a 3-bar rest followed by a first ending which is a measure rest and a second ending with 3 beats rest followed by a quarter note. Instead what I get is a 4 bar rest followed by a double bar line, and then the first and second endings both appearing after the double bar. Please see attached .msc file and the two pdf files created with and without multi-bar rests turned on.

This problem arose originally in extracting parts from a multi-instrument piece. In that example, the extracted parts had "create multi-bar rests" turned on upon creation, and the first ending displayed as extending over the entire piece up to the double bar.

This is with the current MuseScore 1.2 running on Mac OS X 10.6.8.