This issue can be caused by Facebook gadgets.<br /> You will have to check that out by removing each of them until you find the culprit.<br /> If you added or updated gadgets recently then start with those.<br /> Start Firefox in [[Safe Mode]] to check if one of the add-ons is causing the problem (switch to the DEFAULT theme: Tools > Add-ons > Themes). * Don't make any changes on the Safe mode start window. See: * [[Troubleshooting extensions and themes]]