Apparatus: A Hybrid Graphics Editor / Programming Environment [video]
youtube.com
youtube.com
Look at Smalltalk and Pharo on how to do this properly, on the right platform. Not only is Javascript/browser the wrong platform for something like this, but it's also too constraining and limited in scope as to what one can do with it.
It's kind of sad to see bad re-implementations of paradigms that have been out there for 30+ years (in this case even more than that). I suggest that the maintainers of this project go to youtube and watch every Alan Kay video they can find. They'll learn a lot.