You can lock a track to prevent accidental changes. While a track is locked, you can’t record on it, or edit or create new regions. To edit the track, unlock it, make your changes, then lock it again.
Lock a track
Click the Lock button in the track header.
If the Lock button isn’t visible in the track header, choose Track > Track Header > Show Lock Button.
The lock turns green to indicate that the track is locked.
To unprotect the track, click the Lock button again.
Lock multiple tracks
Click-hold a Lock button , then drag the pointer up or down.
The Lock buttons of all swiped tracks switch to the same state.