The extensions is very powerful, go to its homepage in order to find out what it is capable of:

• Download Hyperwords
• Homepage

1. Skip The Installation Delay For Firefox Addons

When you attempt to install Firefox extension, you have to wait for 3 seconds. This protection is for a reason. Even though, if you install a lot of extensions and, being aware of the danger, want to disable the communicate like that:

there is of course a way to do it:

1. Type about:config into the Firefox address bar and hit enter.
2. Paste security.dialog_enable_delay into the filter box.
3. Double click on that preference and change the value to 0

When you try to install addons now, there will be no delay.

2. Disable Warning Messages

That’s a part of basic Firefox configuration, but just in case you haven’t changed these options yet, go to Tools › Options › Security › Warning messages › Settings
In the dialog you can turn off multiple communicates which Firefox uses to make you aware of the low encryption of visited websites.

I turned off all of them, but consider what you’re doing carefully, as for a little time you’re going to earn you sacrifice a pretty useful security feature.

3. Make Firefox Always Remember Passwords

• Download Always Remember Password extension
• Extension’s homepage

This extension Instructs web sites to always remember your password. Some sites like Yahoo Mail, Hotmail, and banking sites instruct the browser to never allow your password manager to retain your information. If you use a shared workspace, then this is probably not desirable. If you are the sole user, then it’s quite handy.
If you want the functionality without the constant presence as an extension, you can use a bookmarklet written by Jesse Ruderman.

4. Add Button To Automatically Run Downloaded Files

• Download OpenDownload extension

In Firefox you cannot choose to run the executable files. You need to download them first and then launch from the Download Manager or directly from your system.

OpenDownload adds a nice button, which probably all former Internet Explorer users are accustomed to, which enables you to run file without having to press the launch button.

The extension downloads the file to your temp directory and then launches it. Your operating system will choose the default application to run it with. After 24 hours the file will automatically be deleted from your system.

Running multiple profiles simultaneously

Obviously, first you need to create at least two profiles. If you don’t know how to do it, I suggest reading profiles guide.
You can normally run Firefox, choosing the profile you need. When you need to run another profile as well, simply run the
/path/to/firefox -P "another profile name" -no-remote
command, where another profile name is the name of the second profile you want to run. Passing the -no-remote switch is what makes it work – normally Firefox insists on running a single copy of program and a single profile at any time.

Windows users can run the command from the command line (Start » Run or Windows + r)

Typing firefox.exe instead of path to firefox should work:
firefox.exe -P "another profile name" -no-remote

I suppose that if you use Linux, you know how to run a command from the terminal.

Run Firefox 2 and Firefox 3 beta on one machine

Yeah, wouldn’t that be great to see what’s new? You can easily compare the new version with you Firefox by opening them at once.

Download Firefox 3 beta

Install Firefox 3 (carefully!):
you have to install the beta version of Firefox 3 into a new directory (for safety choose Custom during installation and make sure you do not overwrite the old Firefox folder).

WARNING: From now on always run profiles with a command including the full path to Firefox – running
firefox.exe -P "main_profile" would update you main profile to Firefox 3 beta and you probably do not want it!

Run Firefox 2 and create a new profile running the command:
/path/to/firefox2 -profilemanager -no-remote

It will be necessary for testing, I called it Firefox 3 beta. Close the Profile Manager window and run the command:
/path/to/firefox3 -P "new profile name" -no-remote
Of course, you need to substitute Firefox 3 beta with the name you gave to your new profile. For me, the path to Firefox 3 under Windows is
C:\Program Files\Mozilla Firefox 3 Beta 2\firefox.exe
and I called the new profile Firefox 3 beta so I run Firefox 3 with Windows + r and
"C:\Program Files\Mozilla Firefox 3 Beta 2\firefox.exe" -P "Firefox 3 beta" -no-remote
command.

You’re done – you should have Firefox 2 and Firefox 3 running simultaneously.

Table of contents

Customize toolbars:

• Stop-or-Reload Button extension
• Advanced modification of the toolbars – userChrome.css
• Remove the Edit and Help menus
• TinyMenu extension
• Menu Editor extension
• Remove disabled Back, Forward and Stop buttons
• Remove padding from the navigation buttons
• Remove the Go button in the location box and the magnifying glass in the Search box

Bookmarks Toolbar

• Organize your bookmarks in folders
• Smart Bookmarks Bar extension
• Favicon Picker 2 extension

Tabs

• Customize the display and location of the close tab button on the tab bar
• Don’t use bold text on the active tab
• Reduce tab width
• Make the active tab wider
• FaviconizeTab extension
• ColorfulTabs extension
• Vertical tab bar – Vertigo extenion

More

Customize toolbars

Let’s have a look at the standard interface. From the top, we have: menu bar, navigation bar, bookmarks bar and tab bar:

First of all, let’s consolidate them into one or two bars (depending on the resolution and the size of your screen).
Open View » Toolbars » Customize... window.

Tick the Use Small Icons box. Now the fun begins. You can drag and drop all the icons and boxes from the window to the toolbars and remove whatever you want from the toolbars. It is not possible to remove the menu here, so let’s use the menu bar first. I suggest moving the menu items to the right as you probably do not use them very often.

So, drag the navigation buttons to the menu bar. If you are accustomed to the Alt-Home shortcut, you can safely remove the Home page button. Location box suits in the space between navigation buttons and menu items. I use Smart Keywords instead of Search box so I removed it.
Activity Indicator (spinning circle in the upper right hand corner) is unnecessary as well as status bar includes a page loading progress meter. You can also remove it using userChrome.css, I’ll describe how to do it later on.
Finally, you can add some Spaces to the bars to make it look clearer.

I managed to put everything in the menu bar so I unticked View » Toolbars » Navigation Toolbar Here’s the result:

Stop-or-Reload Button extension

Download Stop-or-Reload Button extension

You probably do use stop and reload buttons. But as they are never necessary together, why don’t you merge them into one? Once you install the extension, you will only see just one of the buttons at a time.

Advanced modification of the toolbars – userChrome.css

If you don’t know, check what userChrome.css is.
By adding a few lines you can get rid of anything you don’t need in the menu bar so that you can see as much of the current web page address as possible. So, let’s edit userChrome.css.

Remove the Edit and Help menus

If you want to remove the Edit menu, you need to memorize some keyboard shortcuts:
Copy Ctrl-C; Paste Ctrl-V; Find Ctrl-F; Find next Ctrl-G; Select All Ctrl-A.

Probably you do not use Help menu as well. However, you can always access Help with F1 key.

I use Ctrl-H to access History so I removed this menu as well.

To remove the menus that you do not need, add the following lines to your userChrome.css:
/* Remove the Edit and Help menus */
#helpMenu,
#edit-menu
{ display: none !important }

Id’s for all the menus are:
file-menu, edit-menu, view-menu, go-menu, bookmarks-menu, tools-menu, helpMenu
If you want to remove more menus, just add the #’s with their names after commas, e.g.:
/* Remove Edit, History and Help menus */
#helpMenu,
#edit-menu,
#go-menu
{ display: none !important }

TinyMenu extension

Download TinyMenu extension
HomePage

If you don’t like the idea of removing menus or need to compress it even more, consider using the TinyMenu extension, which replaces all the menus with a merge one and leaves just one dropdown menu in the bar.

Menu Editor extension

Download Menu Editor extension

This small extension is probably one of my favorite. It allows you to remove any entries from the menus in the menu bar and from the context menu (right-click menu) as well.
Install it and open its options:
Tools » Add-ons » Menu Editor Options
A simple menu lets you untick all the entries which you do not want to see.

It lets you make your menu look really transparently, no matter how many extensions you’ve installed. To get the idea, have a look at my context menu:

Remove disabled Back, Forward and Stop buttons

The following tweaks remove the buttons when they are not necessary: Back button when there’s no page to go back to, Forward button when there’s no page to go forward to and Stop button when there is no page loading. Otherwise, they dynamically appear.

Open userChrome.css and add the following lines:

/* Remove Back button when there's nothing to go back to */
#back-button[disabled="true"] { display: none }
/* Remove Forward button when there's nothing to go forward to */
#forward-button[disabled="true"] { display: none }
/* Remove Stop button when there's no page loading */
#stop-button[disabled="true"] { display: none }

If you add the code below instead, you won’t see the Back/Forward if there’s nothing in browser history, the View Background Image if there’s no background image, the Cut/Copy/Delete if there’s no text selected, Paste menu item if there’s nothing in clipboard, the Reload All Tabs/Close Other Tabs/Close Tab on tab bar context menu if there’s only one tab opened.
/* Remove all disabled menu items */
menuitem[disabled="true"] { display: none }

As I mentioned before, I use Alt-Home shortcut instead of Home button. I removed it using View » Toolbars » Customize... window but you can also remove it via userChrome.css:
/* Remove Home button */
#home-button { display: none }

The Activity Indicator (circle in the upper right hand corner) can be removed via userChrome.css as well:
/* Remove Activity Indicator */
#throbber-box { display: none !important }

Remove padding from the navigation buttons

This userChrome.css tweak makes toolbars use less space around buttons, leaving more space for actual web pages. It alo affects additional toolbars (e.g Googlebar).
/* Remove extra padding of the navigation buttons */
.toolbarbutton-1, .toolbarbutton-menubutton-button
{ padding: 2px 3px !important }
.toolbarbutton-1[checked="true"],
.toolbarbutton-1[open="true"],
.toolbarbutton-menubutton-button[checked="true"],
.toolbarbutton-menubutton-button[open="true"]
{ padding: 4px 1px 1px 4px !important }

Remove the Go button in the location box and the magnifying glass in the Search box

I always hit enter after typing the address or the search query. Probably so do you. So you don’t need these buttons:

/* Remove Go button */
#go-button-stack, .search-go-button-stack
{ display: none !important }

/* Remove the magnifying glass in the Search box */
.search-go-button-stack { display: none !important }

What I achieved until now:

Bookmarks Toolbar

Organize your bookmarks in folders

I consolidated the Menu and Navigation bars. Nevertheless, I like to have a good access to my Bookmarks toolbar so I’m leaving it. But it can still be optimized.
Start with organizing your bookmarks in folders if you have a lot of them. (right click on Bookmarks bar » New Folder…). Give short, relevant names to the folders and single bookmarks. The easiest way to do it is via the sidebar. Press Ctrl-B. You can drag and drop separators and bookmarks in it. Right click allows you to add separators and folders. Just play around with it for a while.
I’ll describe how to edit the Bookmarks Toolbar. Bookmarks visible on it are placed in the “Bookmarks Toolbar Folder”.
If you can’t see the bookmarks toolbar, click
View » Toolbars » Bookmarks Toolbar It is really useful.

Smart Bookmarks Bar extension

Download Smart Bookmarks Bar extension

This extension hides bookmarks names an only shows them on mouse over.

You can modify its actions via
Tools » Add-ons » Smart Bookmarks Bar Options

Hide bookmarks names with no favicon option is responsible for hiding names of bookmarks of pages which do not have favicons – these bookmarks have the standard favicon assigned. I advise leaving it ticked. You can always use the next extension – Favicon Picker 2 – to solve this problem.
You can also make spaces between favicons smaller and auto-hide Bookmarks Toolbar (I personally find it irritating).

Favicon Picker 2 extension

Download Favicon Picker 2 extension

It is very useful combined with Smart Bookmarks Bar extension.
After installing it, you can change favicons assigned to your bookmarks.
One way to do it is via options window
Tools » Add-ons » Favicon Picker 2 Options
However, it is simplier to do it with a right click on a bookmark and then a click on Properties.

Click Browse and find the favicon of your choice. Click OK. You should see the change now.

Some favicons collections:
Delta Tango Bravo
MpP Favicon Gallery
You can always google for more.

Tabs

Customize the display and location of the close tab button on the tab bar

You can edit this preference using about:config page. I will write about it in the future. If you do not now what it is, do not worry. Just enter about:config in the address box. You will see a page with hundreds of preferences. Find browser.tabs.closeButtons and double click it.

You can enter following values in the window which appears:

0 – display a close button on the active tab only
1 (default) – display close buttons on all tabs
2 – don’t display any close buttons
3 – display a single close button at the end of the tab bar (Firefox 1.x behavior)

Choose which suits you the best, type it and click OK.

Don’t use bold text on the active tab

If you do not want the title of the active tab to be bold, add the following code to your userChrome.css file:
/* Make the active tab not bold */
tab[selected="true"] { font-weight: normal !important }

Reduce tab width

If you do not have a widescreen and tend to open a lot of tabs simultaneously you may irritate because of the scroll which appears on the tab bar.

The scroll appears when the tabs are at the minimum width and still cannot fit in the Firefox window. The solution is to change the minimum width of the tabs. The default value is 100 pixels. Change it to around 75 pixels. The titles are still readable and more tabs fit in the screen.
Press Ctrl-L (move the cursor to the location bar) and type about:config. In the Filter box type browser.tabs.tabMinWidthDouble click on the preference name and change the default value in the new window to 75. Click OK.

Alternatively, you can type value 0 which, when necessary, makes titles disappear and leaves favicons only.

Make the active tab wider

Whilst 75 pixels should be enough for background tabs, the active one can be wider so that you can easily read its title. You just have to add the following lines to your userChrome.css: /* Make the active tab wider */
tab[selected="true"] { min-width: 200px !important }
I chose 200 pixels, probably 150 pixels should be enough for you.

FaviconizeTab extension

Download FaviconizeTab extension

You will find this extension useful if you tend to keep some tabs opened all the time, e.g. Gmail or Google Reader.
You can place them in the beginning and minimize these tabs to the size of a favicon.

You can either faviconize tabs by clicking on them or make faviconizing automatic by adding addresses of the websites which you want to always open in faviconized tabs.

ColorfulTabs extension

Download ColorfulTabs extension

ColorfulTabs extensions simply assigns colors to your tabs so that you can simply distinguish them.

The extension lets you choose the fading level of the tabs colors.

Vertical tab bar – Vertigo extension

Download Vertigo extension

Maybe you would like to have a vertical tab bar instead of the default one. You can simply achieve it with Vertigo extension.

It allows you to change the width of the bar.

More

Description of Firefox configuration files, including userChrome.css
Chrome element names and IDs
userChrome.css tweaks

You can keep one Firefox installation with different, independent preferences, looks and sets of extensions.
When you launch Firefox, it can ask which profile to run.

Is it really useful? It depends on how you use your browser. It may be a good way to secure your passwords and not waste system resources on dispensable tasks performed by extensions which you do not currently need.

Set multiple Firefox profiles

Start with closing Firefox (all windows, including downloads).

You need to open the Profile Manager.
In Windows you need to press Windows key + r to open the run line.

A new window will appear. Type firefox.exe -ProfileManager

In Linux, go to the Firefox directory and start Firefox with ./firefox -ProfileManager command.

Once you get the Profile Manager window, you need to be careful. Otherwise, you may easily remove your existing profiles including all the settings.
Managing profiles is pretty straightforward from now on. Let’s add a new profile.

Press “Create profile” button.

You will run Create Profile Wizard. Click Next.

Choose a rational name for your profile (e.g Work or John) and optionally change the profile directory pressing “Choose Folder…” button. Click Finish.

That’s it! You have successfully created a new profile. You will probably want to untick the “Don’t ask at startup” box in the Profile Manager. Otherwise, Firefox would open the same chosen profile every time it would be run. If you untick the box, it will run the Profile Manager at startup.

Shortcut to the chosen profile

If you use your default profile most of the time, choosing it at each startup of Firefox may get a bit irritating. However, you can bypass it by creating a shortcut to the chosen profile or running Firefox from the command line with appropriate flags.

You can select the profile you want to run with -P flag. Let’s try it. Close Firefox, open the command line (Windows key + r for Windows) and type firefox.exe -P "name of profile" (case sensitive, include quote marks!). Firefox will open the chosen profile without opening the Profile Manager window.

Now we can create a shortcut to the specific profile. Right click on the Desktop or in the desired folder and choose New » Shortcut.

In new window type the path of firefox.exe file with the profile flag, normally "%ProgramFiles%\Mozilla Firefox\firefox.exe" -P "name of profile" will work for Windows.

Click Next, type the desired name of the shortcut and click Finish. You get a new icon, which opens Firefox with the profile you selected.