differently-sized noteheads collide in polyphony

[Robin Bannister]

>

\paper { ragged-right = ##t }
teeny = \set fontSize = #-3
<< % seen with versions 2.12.1, 2.10.33, 2.8.8
 a'2 
 \\ 
% \once \override NoteHead #'X-extent = #'(0 . 1.3) % crude workaround to avoid
 \teeny a'4 % voice2 colliding with larger voice1
> >

It looks like the collision avoidance is positioning the second note
as if the first notehead was the same size as the second notehead. 

Issue 428 has a related title but is concerned with articulations. 


Cheers,
Robin