NoteColumn shift in one voice affects dot position in another voice

[Nick Payne]

See below. When I shift the first note in voiceTwo to avoid a collision 
with the note in voiceFour, the dot on the rest that begins voiceOne 
gets separated from the rest and pretty much disappears under the 
following accidental. It looks to me as though Lilypond is trying to 
keep the dots for the rest in voiceOne and the A in voiceFour vertically 
aligned, regardless of whether the rest and the A are vertically 
aligned. You can see this quite clearly by setting the hshift value to 
something larger such as #2.

\version "2.13.9"

\relative c'' {
    \time 3/4
    \new Staff
<<
    \new Voice { \voiceOne r8. <fis d>16 e2 }
    \new Voice { \voiceTwo \once \override NoteColumn #'force-hshift = 
#-0.8 e,4 cis'8 e, <a cis> e }
    \new Voice { \voiceFour a,2. }
>>
}

Nick

noshift.png
Description: PNG image

shifton.png
Description: PNG image