Does that item in the drop-down list has a key icon in front ? If not then this is form auto-fill data. You can use these steps to remove saved items from an autocomplete drop-down list. #click the (empty) input field on the web page to open the drop-down list (or type a few letters) #highlight an entry in the drop-down list with cursor Down key<br>do not click the mouse or press the Enter key #press Shift+Delete (68+) or Delete to delete the highlighted entry Note that hovering with the mouse doesn't work. *https://support.mozilla.org/en-US/kb/remove-websites-address-bar-suggestions