[DiapDealer]

First off: Kevin's right. Session saving is not something Sigil's ever going to do under our watch. Pretending text editors doing it is even remotely comparable will not change that. Nor will throwing out words like QSettings and believing it's some magic switch (that could be used to save the session in a couple of lines of code) help to accomplish what you want. Sigil uses QSettings. It's not a lack of knowledge that is keeping us from doing what you want.

There's no such thing as a "broken" text file. Text editors don't need to verify that markup is sane before autosaving. Text editors don't need to make sure that the text in an opf file is spec compliant and machine parseable. In short... text editors don't need to worry whether or not text files will "function" properly when saved and restored. Because text editors only need to worry about opening files, displaying them, and letting users change them. Text editors rarely parse the markup in text files. Sigil doesn't have that luxury. In fact in a lot of cases; an auto-save (or session-restore) feature in Sigil would do more harm then good.

It's not happening. The End.