I found this very useful until I tried to log in to the Interactive Investor site. Trying to log in on the front page, the screen went blank and there was a message - "Application error: a client-side exception has occurred (see the browser console for more information)." I looked in the Browser Console but couldn't understand anything there. Deleting this add-on cured the problem and it worked with Chrome with the add-on installed, so it is a Firefox interaction issue. Please fix it so I can re-load an otherwise useful add-on.