SPDCHK, the same thing happened to me last time they changed forum software here =) Irritated me for most of a day (I was popping on and off a lot that day) Whenever I have strange browser problems like that the first thing I do now is a global history/cache and cookie deletion, in every occasion where weird browser behavior was noted by myself it's worked, here and on many other sites.
Unfortunatly only a moderator can lock or change a thread in that manner. Personally I would like starters of a thread to have more control over that particular thread. I've seen too many hijacked threads and off topic junk.
I mean seriously, does it really make sense that the person that started a thread on a particular subject can't control the content of that thread?