I'm not sure exactly what I learned about stateful app design using session variables in PHP, but something wasn't behaving as expected, and I never did figure out what I was doing wrong but I managed to work around it to my satisfaction.
A while back when I was toying with project names, I said I would call this app v1.0 when I had all 4 elements of the "CRUD" (Create, Read, Update, Delete) design pattern working. And somewhere, in that post or another, I described "Delete" functionality as an "afterthought" in the "Update" interface, but in fact a) there was a lot more to it than that.
And b) it didn't take as much work as the "Update" part, but I built in something I don't think I've ever seen in any other web-based CRUD app before - a "last chance" feature that scrapes the POST data after the SQL DELETE, to enable re-SUBMIT'ing to the CREATE module.
There's just a couple little quirks left to unquirk, the most annoying of which is something with the SQL retrieval in the revision module that fumbles quote characters in the title element.