Thanks for you nice words and comments!
Yes, that’s a bug that unfortunately got introduced in Alpha 6. We are on it and plan to issue a quick update – because that thing is annoying! 😉
All future alpha and beta updates will be free. But when we reach the final, it will be $79 USD as a one time fee (no subscription). You will also be able to download a free trial that works fully for 14 days.
Manipulating raster layers (reference layers) are not decided yet. Our original plan was to only import raster into reference layers and then have the user refine those imported drawings on a normal layer on top. That’s why they are called reference layers. During animation you will normally redraw (refine) your drawings a few times anyway, right?
We do already have a clever stabilisation built in working at all times already. It is quite subtle though, but powerful. We are considering additional smoothing on top, but that’s undecided at the moment.
Perspective grids are on our todo list for future updates.