Problems with 'q' in tablature

[Marc Hohl]

Hello,

I am currently engraving a piece and wanted to use the 'q' chord 
repetition for the first
time. I have standard notation and tablature combined and since all 
articulation information
is removed from the content of 'q', the string information has also 
gone, so the tablature
is wrong. Is there any chance to provide a workaround or to include the 
string information?
Otherwise, the functionality is not very suitable for common guitar 
notation.

Here's a minimal example:

\version "2.13.13"

Guitar = \relative c' {
 % Intro
 r8 < gis\4 cis\3 b\2 > ~ q4 q8 ~ q q4
}

\score {
   \new StaffGroup <<
     \new Staff {
   \new Voice { \clef "treble_8"
                \override Voice.StringNumber #'transparent = ##t
                \Guitar }
     }
     \new TabStaff {
     \new TabVoice {  \Guitar }

     }
   >>
}

As the string information is missing, lilypond complains by not being 
able to compute
a suitable string:

Warnung: No string for pitch #<Pitch gis, > (given frets (7 4))
Warnung: No string for pitch #<Pitch gis, > (given frets (7 4))
Warnung: No string for pitch #<Pitch gis, > (given frets (7 4))
Warnung: No string for pitch #<Pitch gis, > (given frets (7 4))

TIA

Marc