#4967 Parentheses on adjacent notes with accidentals collide

[Simon Albrecht]

If immediately adjacent notes with accidentals are parenthesized, the parentheses will collide:

\version "2.19.47"
\relative c'' {
  \parenthesize cis4
  \parenthesize c
  \parenthesize ces
  \parenthesize ces
}

[Simon Albrecht]

The problem only arose with the fix for issue 155 for v2.19.20.