My current browser seems to have a little problem with pop-under windows, which cause the entire application to be sent to the back of the window list, and it’s really annoying. I set up a little Proxomitron filter to deal with this. It’s kind of cute because what it actually does is change the “blur” method that sends it to the back to a “close” method instead, thus making the pop-under go away entirely in a much more straightforward way than happens with pop-up windows. Check it out here.