I finally learned how to change the tablature notation in BIAB. I can't believe that it took me 30 years to look that up.

Anyway, it seems that since BIAB 2014 it has been possible to easily edit tablature so that we can choose what string a note is played on. No more having to export as MIDI and editing in Guitar Pro. Of course, as a guitarist I suck at sight reading. As an Italian, I learned my notes with the Do, re, mi, sol nomenclature and I am at a point where I can no longer read charts that use SOL, DO, RE, etc, but when reading a musical staff if I see a C I have to first think "Do" then translate to "C". It's annoying.

However, while playing with this feature, I think I found a bug (or maybe a limitation of BIAB) that left me a bit perplexed.

I found an exercise I have had since the Paleolithic and I loaded it in BIAB. Simple arpeggios for piano.

Armed with my newfound knowledge of how to edit a tab, and since a dozen bars of this exercise are way up on the staff, needing more than 7 lines above staff to display, I decided to transpose down an octave so it would be playable on guitar.
Funny enough, BIAB must have already transposed the tab lower because it would have been way out of range for any guitar longer than 2 inches.

Anyway, when I transposed down to -12 in the dialog box, nothing happened to the tablature. As I expected.
However, the notes were still around the 22nd fret, so I wanted them in the middle of the fretboard.

I transposed down another octave and... no dice. The notes changed but the TAB didn't.
I transposed another 12 semitones, same thing.

Finally, I tried CTRL-Alt-5 (transpose a semitone down) and that worked, except I had to do it 12 times for it to go down an octave.

What did I do wrong? Or is this just the way it is?

Thank you.