Alternate (scheme) text spanner ignores spacers

[Rutger Hofman]

Hello list,

David Nalesnik wrote a scheme TextSpanner that honours the spanner-id 
predicate. This is really, really great: I no longer have to create new 
Voices for overlapping TextSpanners. But it has a feature/bug that is 
really unwelcome: if the \stopTextSpan is after a spacer note (maybe by 
using David Kastrup's now famous \after), this spacing is ignored. The 
right-bound text appears immediately after the 'true' note.

Two observations:
 - the standard TextSpanner behaves correctly
 - the TextSpanner in scheme, which David N. used as an example, also 
has the feature/bug

Alternate text spanner:
https://lists.gnu.org/archive/html/lilypond-devel/2015-10/msg00042.html

Attached a minimal example of correct/buggy behaviour, and, for ease of 
reference, David N.'s implementation.

I would dearly love to see this fixed, but I have no idea where to look.

Rutger Hofman
Amsterdam

delay-ES.ly
Description: Text Data

text-spanner-id.ly
Description: Text Data

text-spanner-no-id-clipped.png
Description: PNG image

text-spanner-with-id-clipped.png
Description: PNG image