I noticed the same problem too, but it seems like only some things show up, like new articles or something and older ones don't.
In mine, Null's Diner shows up, and that's a new article from a few days ago, but the other day, I went back to an older article, Mochi's Mocha, to add something in the sidebar, and it doesn't show up in the Continue Working widget. Other things I've edited like blocks, maps, map markers, historical entries, and content trees have all shown up in this widget no problem. It seems like it's only pertaining to articles.