\header { tagline = ##f }
{
  \key e \major
  \time 3/4
  r4 r g'
  \once \override TrillSpanner.stencil = ##f \pitchedTrill dis''2.
  \startTrillSpan ees''
  \key aes \major
  <ees'' c''>4 \stopTrillSpan q q
}
{
  \clef bass
  \key e \major
  \time 3/4
  gis2 e4
  \once \override TrillSpanner.stencil = ##f \pitchedTrill <gis fis>2.
  \startTrillSpan <aes ges> %%% wrong %%%
  \key aes \major
  g?4 \stopTrillSpan g g
}