Go to the affected URL (http://www.verkeerscentrum.be/verkeersinfo/kaart?type=HTML&region=antwerpen). This a traffic information website. On the top right side is a very handy checkbox, marked "automatisch". This will update the page content every 5 minutes. Since Firefox 14.0.1, when the browser is to refresh the page, an annoying Firefox pop-up window (no, not a website pop-up!!) will come ask for confirmation. I don't find an option to disable this. Consequence: either use another browser, or forget using the site's very interesting auto-update feature. Did I miss the configuration item? If so, where can I find it? Or is there another solution? Thanks