Re: Grace notes in multiple voices << {} \ {} >>

[Keith OHara]

MusFelix <musfelix <at> live.com> writes:
> 
> Thanks.  I'll try a hidden grace in the other voice to see what that
> produces.
[...]
>     << { \appoggiatura fs'8 es8( ds es-.) }
>     \\ { gs,4 b8}
>     >>
> 

Based on your posted image, it looks like you are seeing the problem where
Lilypond forgets the voiceOne setting, if she is asked to switch to grace-note
settings immediately after setting up the voiceOne.

(As explanation, << \\ >> is a short-hand notation to set up two voices,
one with voiceOne and the other with voiceTwo settings.)

Probably you will get correct output if you re-affirm that you want the 
upper voice set as voiceOne : \appoggiatura fs'8 \voiceOne