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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)
23,053 users

ChatZilla Requires Restart

A clean, easy to use and highly extensible Internet Relay Chat (IRC) client.

Rated 4 out of 5 stars (150)
21,578 users

Open Google Calendar

Adds the Google Calendar web interface in a new Thunderbird tab. Creating and viewing events works like in a browser (Firefox, Chrome, ...)

Rated 4 out of 5 stars (31)
18,214 users

StartupMaster

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

Rated 4 out of 5 stars (289)
14,973 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/email without the need for a separate calendar program.

Rated 4 out of 5 stars (534)
14,782 users

FireTray Requires Restart

A system tray extension for Linux and Windows, allowing to set up custom icon, hiding to tray instead of closing, display the number of unread messages in mailing applications, and other features ...

Rated 4 out of 5 stars (280)
12,491 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)
12,122 users

MinimizeToTray revived Requires Restart

Minimizes windows into the system tray.

Rated 4 out of 5 stars (395)
10,728 users

Toolbar Buttons

Adds toolbar buttons to the customize toolbar window in several programs including Firefox, Thunderbird and SeaMonkey. Some of the buttons make commonly preformed actions quicker, others add new functionality.

Rated 4 out of 5 stars (369)
7,573 users

ProfileSwitcher Requires Restart

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

Rated 4 out of 5 stars (113)
7,252 users

Dorando keyconfig Requires Restart

A modified Dorando's addon to rebind keyboard shortcuts. It is designed to be a drop-in replacement, keeping your old settings. (See details for upgrade instructions.)

As of version 2016.2, Custom keys (using custom JavaScript) work again!

Rated 5 out of 5 stars (50)
5,898 users

Classic Toolbar Buttons [Tb24-58] (discontinued)

'Classic Toolbar Buttons' add-on restores old toolbar button ui (known from Fx 4-7 small view, Fx4-12 large view & Tb5-14) for current Firefox, Thunderbird and Seamonkey versions.

Rated 5 out of 5 stars (145)
2,533 users

FlashGot Mass Downloader Requires Restart

Download all the links, movies and audio clips of a page at the maximum speed with a single click, using the most popular, lightweight and reliable external download managers.

Rated 5 out of 5 stars (889)
2,004 users

Minimize On Start and Close Requires Restart

A remake of the MinimizeToTray-extension made to fit the Windows 7 taskbar. Instead of minimize the window to the tray it minimize it to the taskbar. It can minimize on startup, when the window is closed and/or when the esc key is pressed.

Rated 4 out of 5 stars (111)
1,842 users

Disable Add-on Compatibility Checks

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

Rated 4 out of 5 stars (120)
1,617 users

Show InOut

Adds two columns to the list of mails. One shows an indicator wether a mail is incoming or outgoing, the other shows the sender or the recipient of the mail respectively...

Rated 5 out of 5 stars (40)
1,545 users

Simple Locale Switcher Requires Restart

An easier management of the user interface language

Rated 5 out of 5 stars (14)
1,498 users

CuteButtons

Adds icons to buttons and/or menus.

Rated 4 out of 5 stars (94)
1,485 users

Image Zoom Requires Restart

Adds zoom and rotation functionality for images...

Rated 4 out of 5 stars (354)
1,326 users

ViewAbout Requires Restart

Enables access to various about: dialogs from the View menu.

Rated 4 out of 5 stars (16)
1,224 users