I'm not sure if this is caused by amazon. There is no single way I can recreate the bug with certainty. However it does seem to happen when I browse amazon. Here's a screenshot of what it looks like: http://i43.tinypic.com/fo1tso.png When Firefox freezes a dialog appears shortly after. The popup window doesn't contain a title or content. It's possible to close the window but a new one appears a few minutes later and during that period Firefox remains frozen (with full CPU usage in one core). The only way to recover is to kill the process and restart. My current theory is that something is making an infinite loop or such. Firefox should normally say something like "Would you like to wait or stop the javascript. [yes] [no]". In my case the dialog which should have buttons is blank. Are there any logs I can check or logging I can enable? Is this a known bug? Are there any commands I can use from the context of an active dialog box? I've tried closing the tab, changing tabs, etc. but nothing seems to work while a dialog box is active. Thanks for any help! :) Annan