Compound Signature

[Alberto Simões]

Hello

I used the snippet bellow to produce "compound" signatures, like  "6-9/8".

But not it is showing:
  could not find this grob's vertical axis group in the vertical alignment

What is wrong? What changed?

Thank you
Alberto

----- // -----

% use as
%   \once \override Staff.TimeSignature #'stencil = #(compound-time "2" 
"3" "4")
#(define ((compound-time one two num) grob)
  (grob-interpret-markup grob
    (markup #:override '(baseline-skip . 0) #:number
      (#:line (
          (#:column (one num))
          #:vcenter "+"
          (#:column (two num)))))))