Two Problems: Appoggiatura and \alternative

[Will Oram]

At the moment I can't break everywhere I want to. After testing the 
problem by breaking after every bar, I can safely say grace notes 
prevent breaks from happening.

a4 b c d \break %%% OK break
e d c b \break %%% bad break
\appoggiatura b8 b1

How can I force breaks on measures like these?

---

Some time ago I discovered that my score block dedicated to programming 
line breaks conflicted with uses of \alternative. In the below example, 
\alternatives will appear correctly. When the % is removed from the 
third line, the brackets over alternative measures disappear. How can 
this be circumvented?

\score {
  <<
        %\spacing
        \context StaffGroup = "strings" <<
         \context Staff = "violin_one" <<
              \set Staff.midiInstrument = #"violin"
              \set Staff.instrument = \markup { \center-align < 
"Violino I." > }
              \barlines
              \theFirstViolins >>
         \context Staff = "violin_two" <<
              \set Staff.midiInstrument = #"violin"
              \set Staff.instrument = \markup { \center-align < 
"Violino II." > }
              \barlines
              \theSecondViolins >>
         \context Staff = "viola" <<
              \set Staff.midiInstrument = #"viola"
              \set Staff.instrument = \markup { \center-align < 
"Viola." > }
              \barlines
              \theViolas >>
         \context Staff = "violincello" <<
              \set Staff.midiInstrument = #"cello"
              \set Staff.instrument = \markup { \center-align < 
"Violoncello." > }
              \barlines
              \theCellos >>
         >>
 >>

  \paper { }
}

Will Oram // Genius @ Large // AIM spamguy21
spamguy (at) foxchange (dot) com // wro1 (at) cwru (dot) edu