Claudio,

It's very rare to see a dim7 chord notated with double flats (even in music from the classical masters such as Mozart, Beethoven, etc.).

BIAB's notation is based on creating lead sheets. It is not a fully comprehensive notation program. I don't know of any way to get double flats or double sharps. To do that, you'd need to use a more specialised music notation program. Musescore is freeware and does a great job if you are looking for something.

Regards,
Noel


MY SONGS...
Audiophile BIAB 2024