Yup. Hmm, "Chrome" is mainstream.
Ummm ... when I referred to "New" above, that was probably irrelevant. You're talking about "Watch This THREAD", not "Watch This Forum".
I never noticed before that I was "watching" a thread and missed any new posts.
Do you have that problem with only one thread and no other thread? I recall that you said that "watch any thread that I post to" works, and you were only talking about the "watch this thread" button.