If you can see in my screenshot, I've got several MIDI layers overlapping on my Impact channel and this can create a mess with arranging. I've got the main pattern layers underneath but the snare is on a MIDI track I've edited to play off beat to give it some laid back swing. I've also got extra percussion sounds and crash symbols on a seperate midi track and would like to be able to play drum pads in for a live feel over my Pattern clips to create more of a live feel. I can see that these multiple midi tracks can be played together, but I'd like to be able to expand them as seperate lanes to make things more manageable. Also if you record a pad over a pattern clip to try and give it an organic feel, it will by default overwrite the pattern and you'll have to put the pattern clips back in underneath the midi clip.