Re: Issue 617 in lilypond: X-offset works in a specific way for RehearsalMarks

[lilypond]

Comment #10 on issue 617 by n.puttock: X-offset works in a specific way for  
RehearsalMarks
http://code.google.com/p/lilypond/issues/detail?id=617

-->8--
The @knownissues could be something as simple as:

Overriding the #'X-offset property to a fixed value causes the
#'self-alignment-X property to be disregarded.  Therefore, it is
recommended to override it with a callback to
ly:self-alignment-interface::x-aligned-on-self, similarly to its
defaut definition.  This method is described in @rextend{Callback
functions}.
--8<---

This is not recommended at all.  The default callback is a closure,  
combining the result of ly:self-alignment-interface:x-aligned-on-self *and*  
ly:break-alignable-interface::self-align-callback.  Thus overriding  
X-offset also causes 'break-align-symbols to be ignored, messing up the  
positioning completely.