Thanks for getting back to me, ag_mike_d, and thanks for the detailed response.
Weirdest thing happened last night: ctrl-f started working again. I am now unable to reproduce my own issue!
Possibly related: I had to reboot my computer yesterday, for unrelated reasons. Near as I can tell, ctrl-f started working right after that.
I do recall past times when I rebooted, because something wonky was going on with things to do with the keyboard. On the other hand, ctrl-f was working properly, before yesterday's reboot, in other contexts; e.g., "Find in page ..." in Firefox and "forward-char" in Emacs.
Who knows. But anyway, thanks again. That page you linked to showed me some new tricks, so the posting still paid off.
