Hello every one
My question is about the piano roll view. I have one midi track for my drum and one midi track for my bass. I can put them one on top of the other using ''piano roll multi-track''. So when i delete a note on the bass track i delete the one that is under on drum track. I want to modify one without changing the other.
 
Thanks.

Disable editing on that track. Make sure the track pane is showing and then use the lock icon just to the left of the track name. You can also choose to show or hide the track there as well.

Thanks Biker.