Comment #43 on issue 2801 by [email protected]: Patch: Approximates cross-staff slurs in VerticalAxisGroup vertical-skylines.
http://code.google.com/p/lilypond/issues/detail?id=2801
Regarding comment #40: can be mostly disregarded as I misremembered. span-bar-articulation.ly would have been the only single-system test flagged in my own issue. It may still be interesting since that is also the only one with significant coloring (suggesting an offset) in the regtest image rather than just dimensional differences.
But could also be due to the larger scale.
