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rikaichan Requires Restart

Japanese to English/German/French/Russian dictionary. Just hover the mouse on top of a word, and a popup appears. Automatically de-inflects verbs and adjectives. Detailed kanji view...

Rated 5 out of 5 stars (132)
31,304 users

Disable Add-on Compatibility Checks

Reinstates the extensions.checkCompatibility preference without respect to the current application version.

Rated 4 out of 5 stars (118)
29,525 users

Thunderbird Conversations

This addon provides a conversation view for Thunderbird, grouping messages together and allowing you to reply "inline" thus providing a more efficient workflow.

Rated 4 out of 5 stars (420)
29,517 users

Rikaichan Japanese-English Dictionary File Requires Restart

This is a dictionary file add-on for the Rikaichan extension.

Rated 5 out of 5 stars (10)
28,834 users

Display Mail User Agent Requires Restart

Displays icon for user agent of received mails.

Rated 4 out of 5 stars (104)
28,202 users

Simple Locale Switcher Requires Restart

An easier management of the user interface language

Rated 5 out of 5 stars (12)
28,048 users

GPO support For Firefox and Thunderbird

For work with new versions, use autoconfiguration module https://mozillagpo.sourceforge.io/
Firefox and Thunderbird extension to manage user preferences and user profile CA certificates using group policy

Rated 4 out of 5 stars (12)
27,419 users

Color Folders Requires Restart

Color your Folder Treeview Icons!

Rated 4 out of 5 stars (124)
27,169 users

Classic Toolbar Buttons

'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!

Rated 5 out of 5 stars (140)
26,715 users

Confirm-Address Requires Restart

Confirm E-mail address before sending mail

Rated 4 out of 5 stars (49)
26,075 users

Copy Plain Text 2 Requires Restart

Copies text without formatting

Rated 5 out of 5 stars (92)
25,954 users

Lightning Calendar Tabs Requires Restart

Displays tabs which allows quick navigation between time periods in Lightning calendar. All views of calendar are supported. Color of tab texts can be adjusted.

Rated 4 out of 5 stars (10)
25,382 users

Restart

"Restart" menu and button, with configurable shortcut key.

Rated 5 out of 5 stars (102)
23,094 users

Font Finder Requires Restart

FontFinder is created for designers, developers and typographers. It allows a user to analyze the font information of any element on a page, copy any piece(s) of that information to the clipboard, and perform inline replacements to test new layouts.

Rated 4 out of 5 stars (77)
22,980 users

ProfileSwitcher Requires Restart

It adds some options to launch easily other profiles and the Profile Manager.

Rated 4 out of 5 stars (105)
22,847 users

Folderpane Tools Requires Restart

Allows for customization of the folder pane. Accounts can be rearranged and the startup folder can be chosen.

Rated 4 out of 5 stars (122)
22,567 users

CardBook Requires Restart Featured

A new Thunderbird address book based on the CardDAV and vCard standards.

Twitter: @CardBookAddon
Forum: https://cardbook.6660.eu/

Rated 4 out of 5 stars (130)
22,048 users

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!

Rated 5 out of 5 stars (118)
21,048 users

QuickNote Requires Restart

A simple note-taking extension.

Rated 5 out of 5 stars (193)
20,461 users

Tiny JavaScript Debugger Requires Restart

TinyJSD is a JavaScript debugger for privileged code running Mozilla products like Firefox, Thunderbird, SeaMonkey. It serves to debug the application as well as extensions written in JavaScript.

Rated 4 out of 5 stars (8)
20,425 users