multiple header again

[Ishizaki]

Hello , just for info.

I noticed today that I embuged current CVS tree by my patch.
The following sample does not work as it should, the header in 2nd score block 
overrides header in 1st score block , so you will see two "2nd movement" instead
of "1st movement" then "2nd movement".

I've not yet found how to fix this, sorry.

------------------------------------------------------------------------
|                         Yoshinobu Ishizaki                           |
|                http://www2c.biglobe.ne.jp/~isizaki/                  |
------------------------------------------------------------------------


\version "2.7.0"

\header {
  title = "title"
  subtitle = "subtitle"
  opus = "opus No."
  composer = "composer"
  dedication = "dedication"
  arranger = "arranger"
  instrument = "instrm"
}

\book{
  \score {
    \new Staff <<
       \new Voice \relative c' {
        c d e f
      }
    >>
    \header {
      piece = "1st movement"
    }
    \layout{}
  }
  %%
  \score {
    \new Staff <<
       \new Voice \relative c' {
         g a b c
      }
    >>
    \header {
      piece = "2nd Movement"
      opus = ""
    }
    \layout{}
  }
}