Alternate fretboard tables can be created. These would be used in order to have alternate fretboards for a given chord.
In order to use an alternate fretboard table, the table must first be created. Fretboards are then added to the table.
The created fretboard table can be blank, or it can be copied from an existing table.
The table to be used in displaying predefined fretboards is selected
by the property \predefinedDiagramTable.