Whenever I have FFXI maximized, my Ventrilo push-to-talk button doesn't work. I have to maximize vent while I'm playing in order to talk.
It doesn't seem like this problem happens when anything else is maximized; for example, I may have an internet window open and I will still be able to use vent.
I went on Vent forums and say that someone else had the same problem, but he fixed it by going to some kind of User Settings on Vista and changed some configurations.
Problem is, the Vent Forum Moderators locked that thread before someone could say how to get to said User Settings and what actual setting to change.