I have modified the "dom.popup_allowed_events" setting in about:config to prevent "click" event popups. Most of the time this works nicely, showing the "Firefox prevented this site from opening..." message which allows me to open the popup manually if the site's functionality requires it. What doesn't work is file selection dialogs. For example, when I try to attach a file to an email in Gmail the file selection dialog doesn't open, but neither does the message show! I have to add "click" to the allowed events string to make it work. I don't know if the correct behaviour would be to allow these kind of dialogs regardless of popup blocking settings or to prevent them but show the message. As it is, I consider this a bug. Does anyone know of a workaround or an addon to help manage popups?