>It has done this every time I have logged in for a week now. So I don't think it is any of those three, unless I've developed an uncontrollable twitch in my mouse hand. :)

Could it be that there is a security in place which intercepts some javascript functions?

At this page, http://www.levelextreme.com/Troubleshooting.asp, there is some notes about some topics in regards to that.