On my XP machine iespell highlights the questioned spelling of a word in the thread. In Vista it does not. The Vista machine is my main computer at home now and I am not a great speller. In long posts I miss the highlighted word. Any comments?
My desktop with Vista works fine and my laptop when running Vista had the same problem you're talking about. I have Win7 on the laptop now and it's doing the same thing it did with Vista.
I don't know what the common denominator is but, I haven't researched it at all. Probably should.