ambitus and break-visibility

[Roman Stawski]

Hi folks

I'm having some difficulty getting break-visibility to work with
ambitus. In the example below I set #'break-visibility to ##(#f #f #f)
which should stop the ambitus from rendering in any position. However,
I still see the ambitus at line ends, in the middle of lines and at
line beginnings.


The example is colour-coded to make it easier to see the problem.
----
\version "2.13.31"
\paper{ ragged-right = ##t }

\layout {
  \context {
    \type "Engraver_group"
    \name WithAmbitus
    \accepts Voice
    \consists Ambitus_engraver
    \override Ambitus #'break-visibility = ##(#f #f #f)
    \override NoteHead #'color = #red
    \override AmbitusNoteHead #'color = #cyan
  }
  \context {
    \Staff
    \accepts WithAmbitus
  }
}

ma = \new Voice \relative c'' { a b c d }
mb = \new Voice \relative c'' { f e d c }

\new Staff {
  \ma
  \new WithAmbitus \mb \break
  \ma \break
  \new WithAmbitus \mb
  \ma
}
----

The actual problem is to display the ambitus at the beginning of a
second line after a one-line intro without having it show up at the
end of the first line.

Does anyone have any bright ideas?

Regards

Roman