Your comments

Hey, love the app!
The ideal way I would see it working is; see how there are dotted frames when there's an audio file, if you have a frame at frame 1 and dotted to frame 30, if you create a frame at 15 NOW it fills the frames before with white... instead it should just HOLD the last defined key until another breakdown is added in between if needed.  That way you'd see frame 1's onion skin when drawing frame 15 too.  If you add another frame at 7, 7 would be onions skin 1, and 1 would be onion skin 2.  Hope this is clear!

This also really helps with having a 'guide layer' which automatically holds while you add keys in other layers without having to copy it (or use a background image) - much more versatile.

Another awesome thing would be to create cycle frames - if you click and drag a frame left it could create a cycle to the frame you drag to which cycles until another key is defined to break the cycle

Also would be very happy to be a beta tester!!  Please get in touch. :)