Advanced Visual Editor missing

My site is at WordPress.com. Advanced Visual Editor worked fine for many many months until yesterday. I updated the theme and it worked again, then the next morning it was gone.

What I mean by gone is that when editing a page it doesn’t seem to even try to load the advanced editor; no spinning wheel, no indication it thought about loading it at all. It looks like it’s just “Visual” (perhaps Tiny MCE) and “HTML”.

What I see in the edit window (either Visual or HTML) is the HTML the Advanced Visual Editor made when it was working, for things like Tabs and such, but no advanced editor interface.

Do you think WordPress.com decided it doesn’t like the advanced editor anymore and is disabling it? Are there other things I can try? I don’t see a plugin for the advanced editor so I don’t seem to have any control over it, wherever it is.

I used to have this all on a hosted server with a wordpress.org installation, but I moved to WordPress.com because security stuff was just such a pain in the keester and cost too much.

Any ideas?