I've noticed something strange in the predefined chord diagrams for guitar. While writing on my book for teaching guitar, I noticed the chord C# diminished is weird to say at the least. The fret diagram is very wrong I'm afraid : http://lilypond.org/doc/v2.13/Documentation/notation/predefined-fretboard-diagrams To be more precise, it shows the use of the third fret on the g-string. Last time I checked, this is A# or Bb. What does this do in C# diminished? Or am I so very mistaken?