Issue 1604 in lilypond: MultiMeasureRest staff position 0 is taken as staff position 2

[lilypond]

Status: Accepted
Owner: ----
Labels: Type-Defect Priority-High

New issue 1604 by address@hidden: MultiMeasureRest staff position 0  
is taken as staff position 2
http://code.google.com/p/lilypond/issues/detail?id=1604

Reported by Olexa Bilaniuk and confirmed with 2.12.3 and 2.13.58:

I have found a bizarre glitch in the handling of MultiMeasureRest's
staff-position property. When setting the staff-position to 0, the
MultiMeasureRest jumps to where it would have been had I set it to 2. The
following use-case triggers the bug:

\version "2.13.58"

\score{
        \new Staff = "Bug" {
                \time 2/4
                \override MultiMeasureRest #'minimum-length = #15
                R2^"Default"\override MultiMeasureRest #'staff-position = #-0.01
R2^"staff-position -0.01"
                \once \override MultiMeasureRest #'color = #red \override 
MultiMeasureRest
#'staff-position = #0 R2^"staff-position 0" %ERROR
		\override MultiMeasureRest #'staff-position = #0.01 R2^"staff-position  
0.01"
                \override MultiMeasureRest #'staff-position = #2 R2^"staff-position 
2"
                \revert MultiMeasureRest #'staff-position
                R2^"staff-position reverted"
        }
}