Fixes a bug (#143) where removing a dynamic child that was the sole member of its SharedBound could corrupt the preceding bound's extent, causing subsequent insertions into the same span to silently fail to propagate their anchor to the parent.
Fixes a bug (#143) where removing a dynamic child that was the sole member of its SharedBound could corrupt the preceding bound's extent, causing subsequent insertions into the same span to silently fail to propagate their anchor to the parent.