I have a document setup where on the left panel is the content from an epub file and on the right is a page with my notes on the content.
Restarts should save this setup. In other words, when I come back to this document after restarting the program, it should retain my setup from the last time I was in the document.
One question, is it enough that the epub and note file return, or are you wanting the epub to return to the same page/scroll position? If the latter, that is a bigger lift. Let me know which you were expecting?