Organmusic with same spacing in staffgroup as above pedal staff

[Wilbert Berendsen]

Hi,

I often use the following structure for organ music:

\score {
  <<
    \new PianoStaff <<
      \new Staff = "upper" { c }
      \new Staff = "lower" { c }
    >>
    \new Staff = "pedal" { c }
  >>
}

But the pedal staff is at a greater distance than the manual staves.
This is caused by the StaffGrouper that's created in the PianoStaff,
and of course this would be desirable for orchestral scores with a
piano part in it.

But I tried to remove the StaffGrouper, by using topLevelAlignment =
##t, so that the spacing would be the same between all staves:

\score {
  <<
    \new PianoStaff \with {
      topLevelAlignment = ##t
    } <<
      \new Staff = "upper" { c }
      \new Staff = "lower" { c }
    >>
    \new Staff = "pedal" { c }
  >>
}

But this seems to hang LilyPond (2.14.2 and 2.15.22) indefinitely. Is
this a bug or is there a better method to use uniform spacing (other
than manually setting staff-staff-spacing and staffgroup-staff-spacing
on the StaffGrouper to the same values)?

-- 
Wilbert Berendsen
(http://www.wilbertberendsen.nl)