First, thanks for all your help. I really do appreciate it.
Second, 'gotcha' on narrowing down the exact add-on. I'm really busy so what I may have to do is disable the whole bit again like we did last night and do the post (I haven't touched anything since last night. I didn't dare. So, it's now 3 PM here, and I have to get this post done sooner rather than later.
I may have time to do the narrowing down of the add-ons tomorrow. For the moment, I'll leave the issue open, pending getting through that without a self-destruct happening. You never know when I'm involved.
And, I apologize for the 'disappearing' comment. It's just that the timing was bad. Suddenly, we have a solution and suddenly you're gone - sorta like, 'OK, that one's fixed. Next?' I should have known, and I'm sorry, really.
So, I've got a post to finish for tomorrow.
Again, thanks for your help. I never in a million years would have guessed a Firefox add-on would be the culprit, esp. since I haven't added any in ages!
Have a good one.