"Dangling" ties.

[Hwaen Ch'uqi]

Greetings,

Is there a way to force LilyPond to engrave ties at the end of a
snippet of music? I was hoping that \set tieWaitForNote = ##t would
work, but it too had no results. Here is the snippet in question:

\score {
  \new PianoStaff <<
    \new Staff {
      \relative c' {
        \key es \major \time 6/8 \clef bass
        r4. \grace { a16[ bes c] } <des f,>4.~ %123
      }
    }
    \new Staff {
      \relative c' {
        \key es \major \time 6/8 \clef bass
        f,,8 r r \grace { s16 s s } <des f des'>4.~ %123
      }
    }
  >>
}

Thank you so much.

Hwaen Ch'uqi