Migrating from Firefox to SeaMonkey browser FAQ

User Help for Seamonkey and Mozilla Suite

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Post Posted February 18th, 2014, 1:44 am

This FAQ is for users wanting to switch from Firefox over to SeaMonkey browser. Someone else will have to cover other components like Composer and Mail/Thunderbird, because I do not use those. I am currently in the process of making this transition myself, so please bear with me.

What is SeaMonkey?

SeaMonkey is the direct descendant of the original Netscape Navigator browser from 1994, it is TMK the oldest web browser in continuous development, and in effect is a piece of living history. There have been many steps to get here, and the project has been called the Netscape browser, Netscape Navigator, Netscape Communicator, the Mozilla Suite, and finally SeaMonkey. The Firefox browser and Thunderbird mail client both are derivative of the original Netscape/Mozilla code. Currently, SeaMonkey is built off of the same Core code as Firefox and Thunderbird, and shares the same rendering engine and many advanced web features and security safeguards.

But isn't SeaMonkey "old fashioned"?

While it's default interface looks "old fashioned", SeaMonkey is not a "legacy" product. It still shares it's Core code with Firefox, and it is a 100% fully-modern web browser capable of rendering any website that Firefox can render, with all of the same underlying security and privacy tools. It also has modern features adapted from Firefox such as Sync, Personas, the searchbar, and Private Browsing. Because it has a smaller development team, SeaMonkey is admittedly a little buggy, but no more buggy than Firefox was when I started using it nearly a decade ago!

So what is actually different between Firefox and SeaMonkey browser?

Forgetting about the various components for now, the most immediately noticable difference between Firefox and SeaMonkey are the tabs. SeaMonkey uses the original style of tabs which were put into the Mozilla Suite way back in 2001, without individal tab closers, with the new-tab button on the left, and no tabs on top. The default arrangement of the nav-bar is also very different from Firefox, and SeaMonkey lacks many of the extra toolbar buttons that Firefox has. The Sidebar is different in SeaMonkey... at one time in the 90's sidebars were all the rage and so SeaMonkey has a comprehensive Sidebar which allows you to manage your addressbook and searches. There are also extensions available to expand the Sidebar in pretty amazing ways. The menu in SeaMonkey is laid out differently than Firefox and it may be confusing how to find some things at first. Also, there are a few keyboard shortcuts which are different. This table shows the shortcuts for en-US on Windows:

Code: Select all
Command                 Firefox      SeaMonkey

Show History Sidebar     Ctrl+H      F9 (whole sidebar)         
Show All History     Ctrl+Shift+H   Ctrl+H         
Show Bookmarks Sb   Ctrl+B/Ctrl+I   F9 (whole sidebar)            
Show All Bookmarks   Ctrl+Shift+B   Ctrl+B         
Private Browsing   Ctrl+Shift+P   Ctrl+Shift+B      
Bookmark All Tabs   Ctrl+Shift+D   (no shortcut)      
Search                Ctrl+K/Ctrl+E   Ctrl+Shift+S   

Urlbar open URL
   in new tab:          Alt+Enter      Ctrl+Enter

How can I make SeaMonkey browser interface like Firefox?

I manage an extension called Sea Fox which fixes most of the major differences between Firefox and SeaMonkey automatically so you don't have to bother with learning a new interface. If you don't want a complete automated make-over, an extension called SeaTab X makes the tabs a little more like Firefox. You can Customize the SeaMonkey interface just like Firefox by right-clicking on the toolbar and selecting Customize. Drag the items you want and change the display to show Icons only. You can also change the following preferences in about:config.

browser.tabs.insertRelatedAfterCurrent (set to false for pre-Firefox 3.6 style)
browser.tabs.autoHide (set to false if you prefer to not hide the tabs toolbar)
browser.tabs.tooltippreview.enable (set to false to hide the tab hover previews)
browser.urlbar.formatting.enabled (set to false to remove url domain highlighting)
accessibility.typeaheadfind (set to false to disable this IMO annoying feature) (set to true to get favicons on all sites like Firefox)

The following userChrome hack will move the New Tab button to the right side of the tab strip:
Code: Select all
.tabs-stack vbox hbox stack { -moz-box-ordinal-group:10!important; }

There are also a few Firefox-inspired themes available for SeaMonkey: ... r-seamonk/ ... -for-seam/

Classic Toolbar Buttons also has SeaMonkey support:

SeaTab-X-2 adds Firefox-style tab closers to SeaMonkey: ... eatab-x-2/

Monkey Fix adds many unique options to SeaMonkey, as well as Bookmarks and History sidebar buttons: ... monkeyfix/

And lastly, Sea Fox adds a plethera of Firefox features to SeaMonkey: ... n/sea-fox/

I used SeaMonkey a few years ago and I didn't like it and it didn't work with some websites, does it still suck?

This was a problem several years ago, but the SeaMonkey developers added the Firefox version number to the "user agent string" so that websites doing "user agent sniffing" will be fooled into thinking they are looking at Firefox. I have not had any problems like this in several months of using it as my primary browser. The SeaMonkey developers have also been migrating Firefox features over to SeaMonkey to make it easier to support so SeaMonkey is now more like Firefox than it was in the past.

Can I keep my bookmarks, history, and passwords if I switch over to SeaMonkey?

Yes! Firefox and SeaMonkey use the exact same back-end to handle most of the stuff in your profile. Start by reading the following article which is concerned with transferring a profile in SeaMonkey: ... _SeaMonkey


sessionstore.js -> rename to sessionstore.json (the file is json format in both)
signons3.txt (if exists)


searchplugins (if it exists)
adblockplus (if you have custom AdBlock filters you want to transfer)
chrome (only userContent.css, not userChrome.css)

Do not transfer the extensions folder or any extensions-related files in the root profile. Also, do not bother transferring prefs.js as it's better to learn the new interface and many Firefox preferences will simply not work in SeaMonkey.

Can I keep my extensions and themes if I switch over to SeaMonkey?

Sadly, there are few extensions and themes officially available for SeaMonkey. If you use Personas (background themes) then those do work with SeaMonkey, and some of the most popular extensions like AdBlock Plus and NoScript are available. You can find extensions for SeaMonkey here: ... sort=users

Also, there is now a tool that can be used to convert extensions from Firefox or Thunderbird to SeaMonkey, run by Lemon Juice. It is not guaranteed to work on everything, but there appear to be quite a few extensions it works with:

(Note: The following site is down as of June 2014 for maintenance issues:)
Some Firefox extensions modified by Philip Chee for SeaMonkey are available here (I cannot guarantee how up-to-date they are):

Philip Chee also maintians a thread here at MozillaZine with links to modded extensions, and users can learn how to modify simple extensions to work in SeaMonkey:

Themes is sadly a much more bleak situation. I'm hoping that Australis will drive some Themers over to the Dark Side with me! So far myself and Frank Lion have built new Themes especially for SeaMonkey... here is the link to SM Themes: ... te-themes/

Can I Sync to SeaMonkey?

Yes! I have no idea how to do this or how well it works, but yes SeaMonkey does support Sync.

I'm visually impared, can I use SeaMonkey?

For starters, the default theme in SeaMonkey uses button glyphs nearly twice the height of Firefox, in nice bright colors for easy recognition. There are also "Go" and "Search Go" buttons in the Customization palette to make the urlbar easier to use. You can use this extension to make the interface use larger fonts: ... e-changer/

SeaMonkey also supports page zoom just like Firefox. In about:config you can change this setting:
browser.zoom.siteSpecific (set to false to use the same zoom level on all pages)
Then press Ctrl+Plus or Menu > View > Zoom to set your global zoom level. Also, under Menu > Edit > Preferences > Appearance > Fonts you can set the minimum font size just like in Firefox.
Last edited by patrickjdempsey on November 9th, 2014, 2:26 pm, edited 6 times in total.
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Post Posted February 18th, 2014, 9:42 am

Session Restore:

SeaMonkey names the file, sessionstore.json.
Firefox names it, sessionstore.js

If you want it, copy it over & rename it. Should work fine (at least it always has for me, with the limited I do in FF).

(Feel free to incorporate or whatever & I can delete this post if wanted...)
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Post Posted February 18th, 2014, 4:05 pm

Another key difference, on Windows at least
Open URL in Location Bar to a new tab:
- Firefox: Alt+Enter
- SeaMonkey: Ctrl+Enter
My Firefox information | Add-ons | GitHub

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Post Posted February 18th, 2014, 4:11 pm

If you bump up the max version for SeaMonkey in the older themes, they will install, and will work fine with a little patching. One can also combine the colour schemes of Firefox themes with SeaMonkey themes by substituting the global subdirectory and mozapps subdirectory. I did that to 4 SeaMonkey themes and they look much nicer that way.


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Post Posted February 19th, 2014, 9:34 am

Any known issues potential migrators should be aware of before deciding they want to migrate?
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Post Posted February 19th, 2014, 1:35 pm

It is a little buggy right now because of some transitions that are happening in Core impacting parts of the browser. Bookmarks backups isn't currently correctly working (or wasn't recently), so it's a good idea to periodically force a backup. I haven't found any other features lately that aren't specifically working, but I also don't use any other components other than the browser.

Something else different... the Findbar in SeaMonkey currently *looks* like the new Firefox Findbar, but it is not per-tab. It's possible they could change the look of it back at some point.
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Post Posted February 19th, 2014, 2:51 pm

patrickjdempsey wrote:Something else different... the Findbar in SeaMonkey currently *looks* like the new Firefox Findbar, but it is not per-tab. It's possible they could change the look of it back at some point.

This is one of the many subtle advantages of Seamonkey over Firefox. Having common findbar for all tabs is a very useful thing for me because I often open multiple tabs in a browser window and search for the same item in each of them. I hope Seamonkey will not change to follow Firefox in this respect.

This is the beauty of Seamonkey that it resists most of the crazy, annoying and cool 'improvements' that are occurring just for the sake of change or trying to be modern but actually degrading user experience. Some examples:

- getting rid of the status bar in Firefox (why it suddenly started to take too much space in the era of large high-resolution displays is beyond my understanding...)
- removing the option to disable javascript in preferences
- making find bar separate for each tab
- inventing 'awesome' bar that is less useful than the traditional Seamonkey location bar
- downplaying usage of windows in favour of tabs to the point it has become impossible to make right-click search to be initiated in a new window
- general GUI madness happening every once in a while (the nearest coming example is Australis)

Hopefully, I'm using Seamonkey so I just sit back and I'm glad I'm mostly unaffected by all this.
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Post Posted February 19th, 2014, 3:00 pm

Having distinct back/forward menus working out of the box has always been a big plus to me. Call me an old fart, but there's less eye parsing needed so you can trust your muscle memory better. In addition we have less stragglers (compared to Firefox) using older versions due to the userbase being niche. Most of the support issues also tend to occur on the TBird side of things due to more non-Core stability. The point really can't be overstated that in a way, SM gets the best out of the rapid release model since you get all the fast track improvements without having to deal with the UI churn that comes with it. There is no mobile/SmOS version of SeaMonkey, so there's no need to compromise in any way in terms of design decisions.

Lemon Juice wrote: - general GUI madness happening every once in a while (the nearest coming example is Australis)

I don't mind working/hacking around UI kinks while testing, but I no longer have the patience/inclination to do it for my main work browser, and SM is really the only realistic option of using an up to date Gecko version without resorting to third-party builds. It's a bit like fiddling with the drape design in a cinema, at some point the amount of effort you expend just isn't worth it. It also helps a lot that most of my key extensions are actively maintained and work on it without any bumping or modification needed. I'm sure a lot of Firefox users are only using the browser because of the added value of the extension system, and switching to another ecosystem is out of the question. Moving to SM will still mainly preserve that advantage.

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Post Posted February 25th, 2014, 2:34 am

In SM the private browsing mode is CTRL + SHIFT + P not CTRL + SHIFT + B as written above.


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Post Posted February 25th, 2014, 3:04 am

In SM the private browsing mode is CTRL + SHIFT + P not CTRL + SHIFT + B as written above.

Nope, in SM 2.24 it's definitely ctrl+shift+B (in en-GB at least).

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Post Posted February 25th, 2014, 3:58 am

I guess you're right for the English version.

But on my French version it's ctrl+shift+P, sure. I do it often.


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Post Posted February 25th, 2014, 4:27 am

I'm sure there are several that are different per localizations, and obviously some localizations won't have Latin characters at all....
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Post Posted February 25th, 2014, 4:35 am

Of course, I now realize that everything I say might only apply to my SM version.

But I didn't notice any other difference in the French version with the keyboard shortcuts above. And I like shortcuts, I would have noticed.


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Post Posted March 11th, 2014, 11:08 am

Other keyboard shortcut differences are Ctrl+digit.
They don't all do something in SeaMonkey, but most used to have various functions in different versions of Netscape.

Code: Select all
Key combi Firefox            SeaMonkey
Ctrl+1    Go to first tab    Activate Browser window
Ctrl+2    Go to second tab   Activate Mail window
Ctrl+3    Go to third tab    Used to be AIM (AOL Instant Messenger) in NS
Ctrl+4    Go to fourth tab   Activate Composer
Ctrl+5    Go to fifth tab    Activate Address Book
Ctrl+6    Go to sixth tab    Activate IRC Chat
Ctrl+7    Go to seventh tab  Used to be Radio in NS
Ctrl+9    Go to last tab     Used to be AIM or Net2Phone in NS

Ctrl+PgUp and Ctrl+PgDn work the same though.
Last edited by Pim on March 15th, 2014, 12:42 am, edited 1 time in total.
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Post Posted March 11th, 2014, 2:27 pm

For me (French versions of SM and FF), it's with ALT and not CTRL in the above mentioned cases.

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