Automatically Locking Performance of Recorded Notes

Under certain circumstances, the performed timing of a note is locked. When the as-performed timing of a note is locked, then any changes you make to the attack location or duration of the note, such as with A+ or D+, will affect only the notated location and duration of the note. Its performance will be unchanged.
 

When you record a performance from your MIDI keyboard, you might or might not want to preserve the fine details of your performance-- the loudness of each note, how close each note is to the beat, and how long the note is.

If your purpose of recording your live performance is just to get notes into the score, and you intend to fine-tune the performance of the notes later, then you will want these recorded notes to be unlocked.

On the other hand, if you want to preserve your musical interpretation of the music as you performed it, then it is a good idea to leave the notes locked. Then, when you clean up the notation, you will not risk accidentally changing at the same time also the underlying performance of the notes-- their loudness, attacks, and releases.

To specify whether the notes recorded at your MIDI keyboard will be automatically locked or not: