FR - 'Fold' like functionality in the midi editor

[braj]

Live4 has a great feature in it's midi editor that allows you to hide piano roll notes that aren't used in your clip. This is cool when dealing with drum programming because you only deal with the notes you need, and for things like bass lines and scales where you know you only want to use certain notes.

I would expand on this basic idea and make it possible to hide all notes except those that fit a specific scale and key, allowing you to quickly lay down midi and never lay a stray note.

Not a very high-priority feature, but it would be nice. On this basic topic, I'd like to see more compositional-based features in the midi editor like this and the already present mirror feature.