Hi,
Still, the output from this doesn't look expected:
\version "2.23.1" music = { c''1 } \new StaffGroup << \new TabStaff
\music \new Staff \music >> \new ChoirStaff << \new TabStaff \music
\new Staff \music >>
Doing some debugging:
\version "2.23.1" \layout { \context { \Score % Force showing all system
start delimiters \override SystemStartBracket.collapse-height = -1
\override SystemStartBrace.collapse-height = -1 \override
SystemStartBar.collapse-height = -1 \override
SystemStartSquare.collapse-height = -1 % Some messages for debugging
\consists #(lambda (context) (make-engraver (acknowledgers
((system-start-delimiter-interface engraver grob source-engraver)
(ly:message "Found ~s from ~s" grob (ly:context-name
(ly:translator-context source-engraver))))))) } } music = { c''1 } \new
StaffGroup << \new TabStaff \music \new Staff \music >> \new ChoirStaff
<< \new TabStaff \music \new Staff \music >> \new ChoirStaff \with {
systemStartDelimiterHierarchy = #'(SystemStartSquare) } << \new Staff
\music \new TabStaff \music \new Staff \music >> \new ChoirStaff \with {
\accepts TabStaff } << \new Staff \music \new TabStaff \music \new Staff
\music >>
This yields:
Interpreting music...
Found #<Grob SystemStartBracket > from StaffGroup
Found #<Grob SystemStartBar > from Score
Preprocessing graphical objects...
Interpreting music...
Found #<Grob SystemStartBracket > from StaffGroup
Found #<Grob SystemStartBracket > from ChoirStaff
Found #<Grob SystemStartBar > from Score
Preprocessing graphical objects...
Interpreting music...
Found #<Grob SystemStartSquare > from StaffGroup
Found #<Grob SystemStartSquare > from ChoirStaff
Found #<Grob SystemStartBar > from Score
Preprocessing graphical objects...
Interpreting music...
Found #<Grob SystemStartBracket > from ChoirStaff
Found #<Grob SystemStartBar > from Score
Preprocessing graphical objects...
It looks like ly/engraver-init.ly is missing
\accepts "TabStaff" in the definition of ChoirStaff.
This causes an intermediate StaffGroup containing
just one TabStaff to be created as a layer between
ChoirStaff and TabStaff to fullfill acceptance
requirements.
If you agree, I'll make a quick patch.
Cheers,
Jean