Firefox issues?

Every so often firefox just decides to spilt pages up into what looks like each frame. Basically it opens new windows for each element of the webpage. Before I upgraded to 1.5.0.1 it would happen every few days or longer. I'd just kill the browser and restart it. Now with 1.5.0.1 it's happening every few hours or so. Is this just happening to me? I don't think it's website related. Konqueror works just fine. Nick