Thanks for working on it !! Some other nits:
https://codereview.appspot.com/571180043/diff/565230043/lily/measure-attached-spanner.cc File lily/measure-attached-spanner.cc (right): https://codereview.appspot.com/571180043/diff/565230043/lily/measure-attached-spanner.cc#newcode93 lily/measure-attached-spanner.cc:93: : ly_symbol2scm ("staff-bar")); If I understand correctly (and I may be wrong, because my knowledge about c++ is more or less zero), then "staff-bar" is a fall-back. I'd create an entry for 'spacing-pair' in define-grobs.scm, too. Similar to MeasureCounter, MultiMeasure Rest and PercentRepeat. https://codereview.appspot.com/571180043/diff/565230043/lily/measure-attached-spanner.cc#newcode141 lily/measure-attached-spanner.cc:141: "break-overshoot " Probably add a regtest for break-overshoot. Or extent input/regression/spanner-break-overshoot.ly https://codereview.appspot.com/571180043/
