I'm currently using mIRC 6.21 in Vista 32bit. If I drag/hold the divider (where the scrollbar is splitting chat windows from userlist) for a while mirc freezes, and I have kill it and restart it. It's not like a major bug in my opinion as this is not something you would do at normal. I was just utterly bored and was messing around when this happened. Though it happens every time I do it. Might be only at my computer this happens though.