#4806 Cross-staff glissando at line break: incorrect slope on first sibling

[Simon Albrecht]

As Harm reported, the fix for issue 1578 (which is probably the same that fixed 664) doesn’t work for cross-staff cases.

:::TeX
\version "2.19.38"

\paper { line-width = 50 }

lower =
\relative c'' {
  \override Glissando #'breakable = ##t
  \override Glissando #'after-line-breaking = ##t
  d,,1\glissando
  \break
  \change Staff = "upper"
  f'''1
}

\new PianoStaff <<
  \new Staff = "upper" { s1*2 }
  \new Staff = "lower" { \clef bass \lower }
>>