smartChord allows individualized tone names and symbols. You can define your personal preferences in the general settings. These settings affect all of the smartChord features.
The chord diagrams shows the notes according the settings. But you can change the setting “Diagram info” to ‘Theory’ so the notes are displayed according the musical theory.
The songbook shows the chord names according your ‘Name settings’ in ‘Tone names’ and ‘Symbol’ settings. The intention is go see always the same chord names independent to the source of your song texts. So you’ll always get a C#, even if the original chord of the song is written as Db. But there is a songbook option to force the songbook to show the original chords. But keep in mind, that with this option activated, the transposing is deactivated!
There is also an interesting setting for the chord diagram info in the instruments ‘Chords’ settings. It allows to switch between the tone symbols, you have chosen in the general settings or the tone names according to the music theory.