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Stationery Requires Restart

Extension to mimic Outlook Express Stationery.
Allow you to use HTML files as templates for mail. Also allow custom template in replies or forwarded mail!

Rated 4 out of 5 stars (120)
27,815 users

DOM Inspector Requires Restart

DOM Inspector is a tool that can be used to inspect and edit the live DOM of any web document or XUL application. The DOM can be navigated using a two-paned window displaying a variety of different views on the document and all nodes within.

Rated 5 out of 5 stars (77)
26,934 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 (434)
24,319 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 (13)
23,749 users

ThunderPEC Requires Restart

ThunderPEC semplifica la gestione della Posta Elettronica Certificata (PEC) e delle comunicazioni PCT e FatturaPA in Thunderbird.

Rated 5 out of 5 stars (11)
23,654 users

Display Mail User Agent Requires Restart

Displays icon for user agent of received mails.

Rated 4 out of 5 stars (111)
23,548 users

MinimizeToTray revived Requires Restart

Minimizes windows into the system tray.

Rated 4 out of 5 stars (389)
23,456 users

Confirm-Address Requires Restart

Confirm E-mail address before sending mail

Rated 4 out of 5 stars (52)
22,113 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 (125)
20,909 users

ExQuilla for Microsoft Exchange Requires Restart

Thunderbird email accounts connecting to Microsoft Exchange Web Services.

Rated 3 out of 5 stars (115)
20,416 users

XNote++ Requires Restart

Persistent sticky notes for Thunderbird associated to mails.
This is a port to Thunderbird >= 3 based on XNote 2.1.0 ( https://addons.mozilla.org/en-US/thunderbird/addon/3093 ) with bugfixes and additional features.

Rated 5 out of 5 stars (72)
20,091 users

SmartTemplate4 Requires Restart

SmartTemplate4 offers an easy way to automatically create customized replies by auto-inserting various mail headers. Templates can be created for every account as well as for the default (all email accounts). Also supports the Stationery Add-on.

Rated 5 out of 5 stars (54)
18,696 users

LightningButton Requires Restart

Toolbar-Buttons for Lightning; advances the feature to get rid of the tabbar.

Rated 4 out of 5 stars (16)
16,580 users

ReminderFox

ReminderFox displays and manages lists of reminders and ToDo's. ReminderFox makes sure you remember all of your important dates via easy-to-use lists, alerts, and alarms, right in your browser without the need for a separate calendar program.

Rated 4 out of 5 stars (532)
16,526 users

Check and Send Requires Restart

Check the message contents and addresses before you send the message...

Rated 4 out of 5 stars (31)
16,190 users

Auto Resize Image Requires Restart

Resizer for inline and attachment images (JPEG, PNG, BMP and GIF image formats).
All platforms are supported (Windows, Linux and Macintosh).

Rated 4 out of 5 stars (33)
15,936 users

StartupMaster

Asks for the master password at startup (fixes multiple password prompt)

Rated 4 out of 5 stars (276)
15,616 users

Flex Confirm Mail Requires Restart

Confirm mail address and attachments based on flexible rules.

Rated 3 out of 5 stars (5)
15,595 users

JavaScript Debugger Requires Restart

As of Firefox 33, Venkman *no longer works*, as the APIs which it needs have been removed.

Venkman is the code name for Mozilla's JavaScript Debugger. Venkman aimed to provide a powerful JavaScript debugging environment for Mozilla based browsers.

Rated 4 out of 5 stars (52)
15,308 users

Calendar Tweaks Requires Restart

Allows several tweaks to the Thunderbird/Lightning calendar user interface including new selection styles and repeating event icons. Mimics the colors and styles found in MS Outlook.

Rated 4 out of 5 stars (57)
14,456 users