Gary, You need to uncomment one of the commented lines:
\context FretBoards % you can use the \with syntax by uncommenting the next line % \with {predefinedDiagramTable = \swing-fretboard-table} Or % or you can use the \set format by uncommenting the next line %\set predefinedDiagramTable = #swing-fretboard-table I’m sorry I didn’t make that clearer. The problem was that you never set your FretBoards context to use the new fretboard table you defined. Carl