One other question for ya, what browser are you using? I thought about it, and I've been experiencing this as well, using Chrome. Firefox has been laggy for me on many sites for a long time, so I stopped using it entirely. I flat out don't trust IE, but tried with it for the sake of comparatives, and it works fine with it. Also Safari and Opera. I put the issues I was having down to my connection difficulties of the last few weeks, which my ISP finally fixed, but then it started happening again after I answered you initially.
Without seeing WHY in Chrome, what it looks like is it's having difficulties with some of the AJAX instructions.
FYI, if you're using Opera, don't use the Turbo option. It interferes with many Java instructions. As AJAX is Java, you can well imagine the weirdness I saw with Turbo enabled.