Customize controls, options and add-ons Customize Thunderbird with add-ons, plugins, and extensions All All articles and threads Thunderbird controls and buttons In English Filelink for Large Attachments Permission request messages for Thunderbird extensions Thunderbird add-ons - frequently asked questions Installing an Add-on in Thunderbird Unified Toolbar How to Install and Use another Language in the Dictionary on Thunderbird Install themes to change the look of Thunderbird Certificates Add-Ons FAQ Open Search Add Search Engine to Open Search How can I digitally sign and encrypt emails? How to Customize the New Mail Sound Installing and Using another Language in the Dictionary How to Customize Toolbars Unable to install add-ons (extensions or themes) in Thunderbird Unable to uninstall add-ons (extensions or themes)