2 % mmrests of second voice should not disappear
4 % the problem is more complex: the mmrest-engraver lives at staff level,
5 % but it seems that we need one per voice.
9 \context Staff
= Viole
<
10 \context Voice
=one
\partcombine Voice
12 % ordering significant ??
13 \context Thread
=two
\relative c''{ R
1 c2 c2 }
14 \context Thread
=one
{ R
1*2 }
21 \remove Multi
_measure
_rest
_engraver;
26 \consists Multi
_measure
_rest
_engraver;
27 \consists Bar
_engraver;