There's a lot of nice things about this UI, well done! The difference between "animation" and "design" modes isn't quite obvious at first glance. The switch doesn't tell you anything, so you have to experiment to find out what it means.
I'm happy to see that you're using Canvas for the published animation. It's the only way to go for artistic animation where content needs to update at every frame -- CSS just isn't enough for that.
Some three years ago, I made a HTML5 animation tool that outputs to Canvas + video:
http://radiapp.com
Despite all the hours I put in, I never managed to figure out a way to turn it into a real product. I think you will fare better :)
I'm happy to see that you're using Canvas for the published animation. It's the only way to go for artistic animation where content needs to update at every frame -- CSS just isn't enough for that.
Some three years ago, I made a HTML5 animation tool that outputs to Canvas + video: http://radiapp.com
Despite all the hours I put in, I never managed to figure out a way to turn it into a real product. I think you will fare better :)