Fun. Quick user experience report: expanded "atoms"; the effort to find the boundaries of the insert was a thing ("where does it start? ah, next sentence.", "oh, I read this bit already, so I'm past the end"); with an unmoved mouse, I tried clicking "atoms" again to toggle the insert away (didn't). Perhaps color the insert?
Thanks for the feedback, there should be a fade-in when the text expands, and there's an option to click again to close, but IIRC it's not enabled on the demo. I think it's unnecessary, but it bothers some people to not be able to close them back up.
