[sciurius]

Transposition and capo are fundamentally different, even though it is easy to believe they are related.

Transposition changes the song. When transposing from A → C every chord in the song becomes 3 intervals higher, e.g. a D chord becomes an F chord. You transpose a song when you need a different key for the singer, or when using a transposing instrument like a trumpet or saxophone. But the chords will sound as played, e.g. an A chord played will sound as an A chord.

Capo is for fretted string instruments only. Guitar, bass guitar, mandoline, ukulele. It makes playing of chords easier, simpler chords, less barrées. With a capo, the chord played will no longer sound as played. With a capo on 2, a D chord played will sound as an E chord.

Now there seem to be two schools of thought. One is: capo 2, write D, play D, sound E. The other one is capo 2, write D, play C, sound D. Personally I have never encountered the latter but some people consider this useful.

To get back to the OP suggestion, the first behaviour modifies the song view, so it would be logical to have this on the song settings page. The second behaviour would be more logical to have on the transpose page. But having two different pages to specify capo would be confusing and the advantages would be mininal.

Personally I'm fine with (and used to) the way it is now.