jQuery Requires Restart
jQuery and jQuery UI embedded in browser
KeePass Helper Requires Restart
Adds a hostname, URL, or email account ID to the application's window name (e.g., that of Firefox or Thunderbird) to make it recognizable to password manager utilities like KeePass.
FolderFlags Requires Restart
Allows users to edit the flags Thunderbird sets on folders.
Display Mail User Agent Requires Restart
Displays icon for user agent of received mails.
Simple Locale Switcher Requires Restart
An easier management of the user interface language
QuickFolders (Tabbed Folders) Requires Restart
The "Swiss army knife" of folders. Turn your favorites into tabs - open folders and subfolders, move mails without scrolling around or searching. powerful + easy.
See new mail at a glance after automatic filtering - supports quickFilters addon!
ThreadKey Requires Restart
Strike the 'T' key to sort messages by thread, strike the 'U' key to sort them unthreaded again, just like the 'G' key switches to Grouped By Sort view
IMAP Received Date Requires Restart
Make the “Received” column in IMAP folders show when messages were actually received.
Restores version numbers for all installed add-ons inside Add-on Manager on Firefox, Thunderbird and Seamonkey.
Block advertisement and access to adult sites
Compact Menu 2 Requires Restart
Add a compact menu button to the navigation toolbar, and hide the menu bar.
Adds icons to buttons and/or menus.
A button to be able to open the profile folder, along with two buttons to create profiles, and also switch the current profile.
Tabs Menu Requires Restart
Adds a Tabs menu to the main menu that lets you easily change between tabs.
Right Links Requires Restart
This extension allows to open links in new tabs with right-click directly and using “long” left-click.
This is very useful for touchpads on notebooks and for mice without middle button.
Xclear Requires Restart
Safari-like icons in the URL, search and find fields to clear their contents.
Linkification Requires Restart
Converts text links into genuine, clickable links...
Add-on for Thunderbird that replaces the built-in notifications with OS native ones. It supports most Linux Desktop Environments as well as Windows 8.1/10.
'Classic Toolbar Buttons' add-on restores old toolbar button ui (known from Fx 4-7s small view, Fx 4-12s large view & Tb 5-14) for current Firefox, Thunderbird and Seamonkey versions.
Beta builds on versions page!
This extension enables true full screen mode in SeaMonkey for HTML5 video players, slide-shows, etc. and also for full screen invoked manually with the F11 key.