Arranging : Time, Tempo, Meter, Key, and Chords : Key Signatures : Key Change Dialog

Key Change Dialog
The Key Change dialog lets you specify the mode (major or minor), the key (from seven flats to seven sharps), the range affected (for example, from Bar 1 to the next key change), and whether or not MIDI notes on pitched tracks are transposed or constrained to key (see Pitched Tracks). The Key Change dialog opens whenever you add or edit a Key Signature marker.
 
Major Keys
Displays the major keys from seven flats to seven sharps.
Minor Keys
Displays the minor keys from seven flats to seven sharps. Pro Tools only applies the natural minor mode.
Sharps
Lets you select any of the sharp keys to seven sharps and C major (or A minor).
Flats
Lets you select any of the flat keys to seven flats and C major (or A minor).
From
Lets you specify where to place the Key Signature marker in Bars|Beats.
To
Lets you specify to where you want the key change to take effect: to the next Key Signature marker, to a selection, or to the end of the session.
Snap to Bar
Snaps the Key Signature marker to the barline.
Edit Pitched Tracks
Enabling the Edit Pitched Tracks option lets you transpose existing MIDI notes on Pitched tracks up or down, either diatonically or chromatically based on the key change, or constrain pitches to the new key. For more information on Pitched tracks, see Pitched Tracks.
Transpose
When the Edit Pitched Tracks option is enabled, lets you transpose existing MIDI notes on Pitched tracks up or down, diatonically or chromatically. For example, if the session is in C major and you are adding a key change to D minor, select Edit Pitched Tracks, Transpose, Up, and Diatonically to transpose notes on Pitched tracks up a whole step and then lower the third, sixth, and seventh scale degrees by a half step. The sequence C, D, E is transposed to D, E, F (natural, rather than sharp as happens when transposing chromatically).
When transposing diatonically, chromatic notes are maintained when changing key. For example, when changing key from C major to E major, the note B-flat is transposed to D-natural. This lets you maintain “blue-notes” when changing keys and applying diatonic transposition.
Constrain Pitches To Key
When the Edit Pitched Tracks option is enabled, lets you constrain pitches to the notes of the new key. This means that any diatonic pitches of the old key on Pitched tracks that are not in the new key are individually transposed to the nearest diatonic pitch of the new key. For example, when changing from C major to D major, the sequence C, D, E, F, G changes to C-sharp, D, E, F-sharp, G.
Constraining pitches to key also constrains any chromatic pitches to the new diatonic scale. For example, when changing from C major to D major, the sequence C, D, D-sharp, E changes to C-sharp, D, D, E.