contextStringTunning separates abnormaly two first lines.

[César del Pino]

> I'm not top posting.
% contextStringTunning separates abnormaly two first lines.
 
\version "2.14.1"

notes = \relative c'' {
 g2 g g g g g g g g g g g g g g g g g g g g g 
 g2 g g g g g g g g g g g g g g g g g g g g g 
 g2 g g g g g g g g g g g g g g g g g g g g g 
}

<<
  % separation between lines 1-2 equals 2-3 lines. 
  \new TabStaff {
    \set TabStaff.instrumentName = "Default OK"
    \notes
  }
>>
<<
 % separation between lines 1-2 NOT EQUALS 2-3 lines
 \new TabStaff {     
   \set TabStaff.instrumentName = "Not OK"
   \contextStringTuning #'bandurria-tuning <aes' des' ges' b' e'' a''>
   \notes
 }
>>