Comment #11 on issue 2836 by [email protected]: LilyPond hangs if NoteHead 'stencil is empty
http://code.google.com/p/lilypond/issues/detail?id=2836
No worries about side effects from this fix.In { \override NoteHead #'stencil = ##f bes1 bes } the flats have overlapped the bar-lines since version 2.14 at least.
