I just read a great entry over on the 1pixelout blog about how to maintain knowledge of a pop-up window and keep communication flowing between page loads of the window opener. It requires that the pop-up window periodically tell the opener who it is. It's a really clever idea that I won't try to summarize here. Check out his blog.
The reason why I am so excited about this is that I was trying to come up with a way to create a "pool" or Text Editor windows for an administration tool. The text editor takes like two seconds to load fully plus the pop-up time. I wanted to try to blur() the window after it was used for editing (rather than closing it) and then just focusing and settings values when it was needed again. The main problem was that reloading the main window would always destroy the reference to the pop-up. Well, not any more baby! Now, it's possible. I just have to build it.