The key (pun intended) to understanding this is understanding the difference between the key signature of the song and the key of the song. When you select the drop down, you are able to change the key signature of the song. Key signature doesn't care about major or relative minor. C and Am have the same key signature.

Yes, you have the option of transposing or not. If you choose to not transpose, it will keep all the same chords with the new key signature (and folks will go "what is that?"). That being said, it's handy to have that feature, because often times you import a MIDI file and the key signature gets set to C, even though the song is in Eb. So, when you look at the notation, you get lots of accidentals that don't need to be there.

When you do select transpose, it is simply going to move the chords however many semi-tones away from the base key signature to the new key signature (and remember the key signature of a major and its relative minor is the same - that's why nothing changes), but it won't change major to minor or vice versa. That's because it's not changing the key of the song, it's changing the key signature of the song.

And that's the global setting for the whole song. You can change key signatures at certain bars when you want the key to modulates for example, but that also doesn't change the underlying chords. You have to do that yourself.

It's all about notation (key signature and whether to display accidentals or not), not the actual key of the song.

John

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