staff fails to wrap and runs off right hand side of pdf

[Gemma]

> I'm not top posting

The pdf resulting from this is broken with the first (/partial 4) bar 
taking up the entire first line then nearly eight bars squeezed into 
the second line before running off the right hand side and the rest of 
the music not being visible.

(The midi is fine.)

I have made a couple of errors (note durations) in my input and when I 
corrected one, I got a third line of music on the pdf, but it still runs
off the rhs. The error I corrected was that the end of the second line of 
treble input should be "c4.(bes16 a16)" not "c8.( bes16 a16)".

It was not until I corrected the beginning of the first line of treble 
input from "<c a'>8. <bes g>16 <a c f>8" to "<c a'>8. <bes g>16 
<a c f>4" that the pdf is correctly formed. This appears to be the 
error which breaks the pdf as if you correct only this error, the pdf 
is correctly laid out.


     \version "2.9.13"
     upper = \relative c' {
        \clef treble
        \key f \major
        \time 4/4
        \partial 4
        
        <c a'>8. <bes g>16 <a c f>8 <a c f>4 <a c f> c'16 bes a g f8. g16 a8.
bes16 c4.( bes16 a) bes4 d8 bes a c a f
        <d g c>4 <d g c> <d g c> \times 2/3 { f'8 e d } c8. d16 bes8. c16 a8.
bes16 g8. a16 f8. g16 a8. bes16 c8.( bes16 a16)
        bes4 bes bes8. c16 d8. e16 e4 c8. c16 c4 f8 g16 a g8 e f d c a bes g
        f8. d16 a8. bes16 c4.( bes16 a) d4 d d d8 e16 f16 e4 c8. c16 c4 \times
2/3 { c8 d e } f8. g16 f8. e16
        d4. c8 bes8. c16 d8 e f e f d <a c>8. d16 <g, bes>8. c16 <f a>8. bes16
<e, g>8. a16 f4 f8. f16 f4

     }
     
     lower = \relative c {
        \clef bass
        \key f \major
        \time 4/4
        \partial 4
   
        r4 <g f'> <g f'> <g f'> r f'8. c16 f8. g16 a4 f d bes f' f,
        c'8. c,16 e8. g16 c4 r << { a'4 g f e } \\
                                               { c2 c } >> d4 c8. bes16 a4 f
        bes8. d16 f8. d16 bes4 r c8. c'16 g8. e16 c4 r <c, c'> <d d'> <e e'>
 <c c'>
        f'8. c16 f8. g16 a4 f bes bes8. a16 g4 g, c8. c,16 e8. g16 c4 r a' f 
        b c d,8. c16 bes8 bes a4. bes8 c4 c c, c f8. f'16 c8. a16 f4
     }
     
     \score {
        \new PianoStaff <<
           \set PianoStaff.instrumentName = "Piano  "
           \new Staff = "upper" \upper
           \new Staff = "lower" \lower
        >>
        \layout { }
        \midi { 
           \context {
       \Score
       tempoWholesPerMinute = #(ly:make-moment 100 4)
       }
     }
    }