connect directed arpeggio

[Helge]

I have a problem with  connecting arpeggio. The arrow of
 \arpeggioArrowDown or -Up vanishes when I connect the arpeggios of two
 staves. You can reproduce it with the example below. Comment out the
 connectArpeggios line and you see arrows.

 Is this a known bug?

 Regards Helge


 \version "2.18.0"

 upperHarpII = \relative c'' {
   \arpeggioArrowDown  <b c>2\arpeggio r
 }
 lowerHarpII = \relative c' {
   \clef bass
   \arpeggioArrowDown  <a e a,>2\arpeggio r
 }

 \score {
   \new PianoStaff \with {
     connectArpeggios = ##t
   } <<
     \new Staff \upperHarpII
     \new Staff \lowerHarpII
   >>
 }

-- 
GnuPG fingerprint: EDCE F8C8 B727 6CC5 7006  05C1 BD3F EADC 8922 1F61

signature.asc
Description: PGP signature