When you load up a dozen or more tabs all at once, Firefox can slow down to a crawl.  Now, you can either choose to stop overwhelming Firefox with too many tabs or you can grab this helpful add-on for Firefox that will only load up the tab you need at the time, with multiple tabs still available. 
Just put it on your Bar Tab.

I have one more Firefox 3.6 about:config tip up my sleeve.  By toggling one setting, you can go from having a drop down list of tabs to a thumb-nailed view of each tab that is open. 
Here is how you too can enable this secret Firefox 3.6 feature.

Oh undo function, what would I do without you? 
Well, I would probably be forced to do it again – but that is beside the point.  I love being able to reopen a closed tab or window in Firefox.  It has saved my rear end many times.  This is just one of those Firefox tips you really should memorize.

Rather than reloading each tab, one by one, wouldn’t you like to reload all your Firefox tabs at once?  Okay, I realize this might not be a need for everybody, which makes it a perfect add-on for the browser. 
Reload All allows you reload all the tabs in the window at one go.   Need to reload most, but not every single tab?  It can handle that too.  It features a selection tool in case you want to reload a [...]

In an effort to simplify the Firefox interface, did you know you can make a few changes in the about:config page to move the close tab buttons around?  I’ll show you how to move it to the far right of the browser, in just six easy steps.
Before the tweak (notice the close tab button is on the tab itself)

After the tweak (notice the close tab button has been moved to the far right)

Now what is the secret?  You [...]

One of the most celebrated new features of Firefox 3.7 is the feature that will bring the progress bar out of the status bar and onto your current tab.  Did you know though that there is an add-on for Firefox that will let you add this functionality now? 
The Tab Progress Bar add-on for Firefox is the add-on you need.  Having the process bar on top of the tab really makes more sense, as far as functionality goes because [...]

Get more control over your tabbed browsing experience in Firefox with Tabberwocky. This add-on for the browser will give you dozens upon dozens of ways to customize the way you work with tabs. 
Some of the features of this Firefox extension include:

Open in new tabs from Bookmarks, History, URL Bar, and/or Search Bar
Open Selected Links in New Tabs
Retain tab history when opening links in new tabs
Show/Hide New Tab button and Close Tab buttons
Highlight unread tabs
Set minimum/maximum tab width
Close tabs [...]

Some people may find the fact that Firefox opens a new tab on the far right of your tab toolbar a blessing and some might find it a curse.  It really has to do with how many tabs you are look at, in one single browser.  For those who are cursed today, I have your solution.  The Tabs Open Relative extension changes how new tabs open up, which means no more tab surfing for you.
Once installed, the Tabs Open [...]

Miss having that close button on your last open tab in Firefox? 
Miss it no longer, because of the help of a creative add-on writer and – well, yeah that is it.  The Last Tab Close Button add-on for Firefox will show the close button on the last tab in Firefox, which closes that specific tab, and not the entire browser.
This seems to be a functionality that some were missing, so happy to see it back (for those [...]

Want to get quick and easy access to the history for one specific tab?  The Tab History Menu add-on for Firefox adds that ability to your Firefox browser. 

By introducing this feature into the browser, for those minimal theme users, you can ditch the backward and forward browsing buttons in your navigation toolbar arrangement.  Via the options, you can set it to display the current page title in history menu if the current tab hasn’t had history yet, and [...]