Comment #2 on issue 2584 by [email protected]: partcombine misplaces slurs http://code.google.com/p/lilypond/issues/detail?id=2584
The patch for issue 1967 is probably working as designed, see comments <URL:http://code.google.com/p/lilypond/issues/detail?id=1967#c26> and <URL:http://code.google.com/p/lilypond/issues/detail?id=1967#c20>. It deals with a different and larger subset of slurs than previously (but not a proper superset if you are willing to ignore spurious warnings) by choice. So it is an intentional change and effect in connection with allowing separate and overlapping named slurs for grace notes.
Since the effect is an expected and conscious consequence of the design, I consider this more like an enhancement request than a regression.
