Banjo chords
It is possible to add chord diagrams for tenor banjo by had, but that is quite a bit of work, since you have to put down the fingering of the chord for every chord used, and so for a C chord you have to write the grip 0023. Typically a painstaking job for the computer...
Adding tenor banjo chord diagrams probably is achieved most easy by using the [Guitar diagrams] from the toolbox 
that is used to add guitar chords. Just change "git" into "banjo" in [Part properties|Chord diagrams] and you're done.
