(X-extent . ,ly:axis-group-interface::width)
(skylines . ,ly:axis-group-interface::calc-skylines);
(meta . ((class . Spanner)
- (object-callbacks . ((Y-common . ,ly:axis-group-interface::calc-y-common)))
+ (object-callbacks . ((X-common . ,ly:axis-group-interface::calc-x-common)))
(interfaces . (axis-group-interface
hara-kiri-group-spanner-interface
vertically-spaceable-interface))))))