You may have an unwanted extension that is modifying sites (or the toolbar area). Try this: Disable ALL nonessential or unrecognized extensions on the Add-ons page. Either: * Ctrl+Shift+a * orange Firefox button (or Tools menu) > Add-ons In the left column, click Extensions. Then, if in doubt, disable. Usually 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. Does that flush the tab? ---- Please report back on anything suspicious you find so others can learn about its bad behavior.