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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)
26,915 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)
15,386 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)
3,213 users

Element Hiding Helper for Adblock Plus

Fight the text ads! Element Hiding Helper is a companion extension for Adblock Plus meant to make creating element hiding rules easier.

Rated 5 out of 5 stars (473)
1,499 users

SQLite Manager Requires Restart

Manage any SQLite database on your computer.

Rated 4 out of 5 stars (354)
720 users

User Agent Switcher Requires Restart

The User Agent Switcher extension adds a menu and a toolbar button to switch the user agent of a browser.

Rated 4 out of 5 stars (336)
634 users

Tiny JavaScript Debugger

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 5 out of 5 stars (8)
498 users

Dafizilla Table2Clipboard Requires Restart

Mozilla applications allow to select rows and columns from a table simply pressing Control key and picking rows/columns with left mouse button.
The selection can be copied to clipboard but the original table disposition is lost making ugly results wh...

Rated 5 out of 5 stars (75)
326 users

SeaMonkey Debug and QA UI Requires Restart

Provides Additional Debug and QA UI for SeaMonkey development and testing.

Rated 3 out of 5 stars (2)
319 users

DOM Inspector Plus! [dm] Requires Restart

Improved DOM Inspector! [dm version]. Box Model new layout & more data, see screenshot!. Horizontal scroll for Dom-Tree, and some more.
Inspects the structure and properties of a window and its contents.

Rated 4 out of 5 stars (6)
253 users

Add-ons Manager - Version Number (discontinued)

Restores version numbers for all installed add-ons inside Add-on Manager on Firefox, Thunderbird and Seamonkey.

Rated 5 out of 5 stars (28)
246 users

Restartless Restart

This 15KB restartless add-on will add a "File" -> "Restart" menu item and a ctrl/cmd + alt + r hotkey to restart Firefox or Seamonkey.

Rated 4 out of 5 stars (204)
219 users

Mnenhy Requires Restart

The primary goal of the Mnenhy project is to make some enhancements to SeaMonkey MailNews/Thunderbird, since there're still plenty of comfort functions missing if compared to Netscape 4.x and other mail and news clients.

Rated 4 out of 5 stars (39)
179 users

Copy Pure Text Requires Restart

Allows to copy selected text as plain text by adding a 'Copy as Text' menu item to context menu.

Rated 4 out of 5 stars (15)
154 users

Live HTTP Headers Requires Restart

View HTTP headers of a page and while browsing.

Rated 4 out of 5 stars (216)
134 users

Stylish-Custom Requires Restart

custom additions to Stylish extension

Rated 4 out of 5 stars (10)
127 users

MonkeyFix Requires Restart

Fixes up numerous SeaMonkey browser interface issues (eg. adding support for popup ALT attributes), as well as adding some handy features for developers and power users (eg. configure source viewer, work online/offline).

Rated 5 out of 5 stars (3)
116 users

Image Zoom (ugly fixes) Requires Restart

An ugly attempt at fixing Image Zoom

Rated 4 out of 5 stars (17)
102 users

WorldIP - Geo Add-on with Security Features Requires Restart

Professional Geo Add-on with security features and advanced network tools. Anti-phishing. Protection against DNS spoofing and fake sites. All DNS records for domain. The real location of web server, country flag, extended information about datacenter

Rated 5 out of 5 stars (124)
101 users

Firesizer Requires Restart

Allows you to resize the window to specific dimensions.

NOTE: Users of Firefox 29 and above must install "The Addon Bar" extension to use this, as Firesizer uses the add-on bar that has been removed in Firefox 29.

Rated 4 out of 5 stars (127)
92 users