string open and fingered as well

[bb]

The fretboard shows fourth string as open and fingered fret one same time. 

Regards BB


\version "2.19.2"
   Cuatro =\stringTuning <  a, d g c' f'>
cmSevenA = { < g'\1 c,\2 g\3 dis\4 ais\5 > } % cd#ga#
\storePredefinedDiagram #default-fret-table \cmSevenA % cd#ga#
                        #Cuatro
                        #"1-1; 1-1;o;o;2-2;" 
    \new FretBoards {
      \set Staff.stringTunings = #Cuatro
      { \cmSevenA \break  \bar "||" } 
    }