i'm working on one that gets around the problem creatively. It creates a 1x1 popunder when you click on any of the NEXT links on a tour and the tiny popunder stays dormant until you leave the site (checks for a cookie that is deleted when you leave) then it expands, brings itself to the front and appears basically the same as a exit popup. now, I cannot guarantee when I will finish it, could be this week end, could be a few weeks from now, but when I do, I'll post it for free.
Thats the kind of guy I am.
