tabFullNotation

[Phil Burfitt]

Am I doing something wrong here? I can't get musical symbols to show with 
polphony.

\version "2.17.8"

upper = \relative c' {  c4 d e f }

lower = \relative c { c4 d e f }

\score {
   \new TabStaff {
       \tabFullNotation
       << \upper \\ \lower >>
       }
}