I had not thought about the paging-back issue until you mentioned it, but I recognize in myself what you have said about it. Our brains and sensorimotor systems

I had not thought about the paging-back issue until you mentioned it, but I recognize in myself what you have said about it. Our brains and sensorimotor systems are developed for direct interaction with the physical world, not through proxies (though we can get pretty good with decent proxies through practice.) On the other hand, being able to search is invaluable, as is the ability to have the footnote pages open in a separate window, if the software does not provide a better option. Finally, I can't imagine a good interface that is not pencil-like for sketching diagrams.