Most likely it is an add-on. To find it, open Firefox's '''Add-ons page''' using either: * Ctrl+Shift+a * "3-bar" menu button (or Tools menu) > Add-ons In the left column, click '''Plugins'''. You can set nonessential and unrecognized plugins to "Never Activate", but anything listed here needs to be removed externally to Firefox. In the left column, click '''Extensions'''. You can always disable and extension here, and often remove it. Often a link will appear above at least one disabled extension to restart Firefox. You can complete your work on the tab and click one of the links as the last step. Can you get rid of it?