The add-on LyricXeeker 1.125 has been added to my add-ons and now Delta Search comes up every time I open a new tab. I want to delete this add-on, but the only options I have is to enable or disable the add-on. How can I delete the add-on?
Extensions that do not have a "Remove" button are installed by other software and are not under control of the Firefox extension manager.
Such globally installed extensions are usually found via a registry scan or are installed in a location that Firefox scans for installed extensions.
Extensions installed this way need to be removed via the settings (options/preferences) of the program that has added this extension or you need to uninstall this program via the Control Panel.
In Firefox you an only disable such an extension.