glissando to a nearby modified pitch doesn't always work inside a triplet

[list_lilypond]

I'm new here and don't know if I can send attachments, so I'll try some
code with proza:

\version "2.16.2"
\relative c' {
  % The following doesn't show the (guitar) slide 
  % that I need in this triplet: 

  \times 2/3 { dis'8\glissando[ d( c)] } 

  % It's not that the slide is obscured by the d-line:

  \times 2/3 { cis8\glissando[ c( b)] } 

  % And it's not that the slide doesn't work at all,
  % because here it does:

  % \times 2/3 { e\glissando d( c) } 

  % I think it's because of the modifier in d#:

  \times 2/3 { e\glissando dis( c)}

  % Although 'coming from below' works:

  \times 2/3 { e,\glissando dis'( c)}
}


Play this in your 2.16.2, then you'll see what I mean.
My OS does not let me upgrade yet to 2.18, that's why I'm using 2.16.2.

My guess is that there is not enough space between the two notes where
the glissando needs to be because the pitch modifier occupies so much
horizontal space that lilypond 'decides' that the lenght of the line
indicating the glissando isn't enough to be visible so that it would
be better to drop the glissando altogether.

Any hints how to get this triplet show the intended slide and pull off?

Thanks,
Joe