Engravers cannot be added at the StaffGroup level

[Xavier Scheuer]

Dear Bug Squad,

This has been reported two times in lilypond-user:
http://lists.gnu.org/archive/html/lilypond-user/2011-12/msg00395.html
http://lists.gnu.org/archive/html/lilypond-user/2012-01/msg00111.html

"Mark_engraver" or "Metronome_mark_engraver" should be moveable to the
StaffGroup (and alike: GrandStaff, ChoirStaff, etc.) context (and work!!).

%%%% Snippet

\version "2.13.24"

music = \repeat unfold 5 {
  \repeat unfold 5 c'1
  \mark \default
}

\score {
  <<
    \new Staff {
      s1*0^"Marks should NOT be above this Staff (i.e. above the Score)!"
      \music
    }
    \new StaffGroup {
      <<
        \new Staff {
          s1*0^"Marks should be above the StaffGroup"
          \music
        }
        \new Staff {
          \music
        }
      >>
    }
  >>
  \layout {
    \context {
      \Score
      \remove "Mark_engraver"
      % same for "Metronome_mark_engraver"
      \remove "Staff_collecting_engraver"
    }
    \context {
      \StaffGroup
      \consists "Mark_engraver"
      \consists "Staff_collecting_engraver"
      % same for "Metronome_mark_engraver"
    }
  }
}


%% Note that it works if we move it to the Staff level (instead of the
%% StaffGroup).  But engravers at the StaffGroup level is required for
%% example if the first staff of the StaffGroup is removed, using
%% \RemoveEmptyStaves (Frenched score).

\score {
  <<
    \new Staff {
      s1*0^"Marks are not above the score"
      \music
    }
    \new StaffGroup {
      <<
        \new Staff \with {
          \consists "Mark_engraver"
        } {
          s1*0^"Marks are above this Staff"
          \music
        }
        \new Staff {
          \music
        }
      >>
    }
  >>
  \layout {
    \context {
      \Score
      \remove "Mark_engraver"
      \remove "Staff_collecting_engraver"
    }
    \context {
      \Staff
      % \consists "Mark_engraver"  % We add this engraver to the
second Staff only
      \consists "Staff_collecting_engraver"
    }
  }
}

%%%% End of the snippet

Cheers,
Xavier

-- 
Xavier Scheuer <address@hidden>