This bug is similar to the othe rone listed but this happens on XP with IE6 which I'd say is a pretty common platform nowadays.
If you put a fckeditor window in a popup create by a parent window and then close the popup - the parent window becomes toast. It stops responding and you need to do an End Now on it and open a new IE6 window.
In this case I'm trying to get a popup that allows editing an email while not losing the context of the users work in the parent window.
I had a look through some of the js code for links to the owner/parent and can't quite tell what's going on (my js is not so good) but it seems perhaps an event is hooked to the owner and perhaps after the window gets closed the parent is somehow still attached to the now gone popup with the editor.
If someone knows more about this bug or why it's happening or how I may work around it or even where to start looking to work on it I'd be happy to see what I can do to fix it, as this method of using it is critical to my application and I'd really like to be able to use fckeditor here.
FCK crashes IE6 on XP when used in popup