The Stop and the Reload buttons in any web browser are interchangeably required – the Stop button is used when a web page is in the loading state while the Reload (or Refresh) button is only needed when the page has loaded either completely or partially.
While browsers like Safari, Opera and Google Chrome use a single button for both Stop and Reload function, Firefox has two separate buttons thus pushing the address and search bar further to the right.
To conserve this otherwise wasted space, you can use the Stop-or-Reload extension for Firefox that will replace the two buttons with a single contextual button as show in the following screenshot.

The extension works on Firefox 2.0 & 3.0, but not with Firefox 3.1 beta.
Find this article at: http://www.labnol.org/software/stop-reload-button-in-firefox/6343/

Reader Comments
You can do the same thing with a Stylish script.
link
Written by Brandon on 01.06.09
A stylish style is also available called “Combine Stop/Reload buttons”
Written by Ashish on 01.06.09
the code from the stylish script can be used directly in the “userchrome.css” file, without installing any extensions.
#stop-button[disabled="true"] { display:none; }
#stop-button:not([disabled]) + #reload-button { display:none; }
Written by gxg on 01.06.09
stop = Esc
reload = f5 or ctrl+R
to much addons slowing down ff
Written by JardeLGs on 01.06.09
Indeed, this can be accomplished with a simple Stylish script. In fact, I might suggest “MBlue Combine Nav-Buttons Vista” ( link ).
It not only combines the stop & refresh buttons, but it also conveniently places this new combination button between the back and forward buttons, making a much more streamlined package.
Written by USBman on 01.06.09
When would you ever have the need to stop a page from loading? What instance do you need this?
Does anyone know of such an extension for IE and Netscape browsers?
Written by Quikboy on 01.06.09
I prefer just using the keys (less mouse movement and much quicker)
F5 to refresh
ESC to stop
Alt+Left Arrow for back
Alt+Right Arrow for forward
Alt+Home to go to your homepage
Written by Rich on 01.06.09
Google Chrome has both stop and reload buttons.
Written by Sai Charan on 01.07.09
It’s a real shame that you have to use extension and code for such a simple feature !!
In my opinion, Firefox is B.S. It’s only good as far as the extensions goes.
Opera Rules for normal browsing.When I need those extensions (rarely) I use FF.
Opera’s built in RSS newsreader and email client is phenomenal…makes it so much simpler to track everything. Mouse gestures make it much simpler browsing (Right mouse button + Left mouse button = Back button; Left mouse button + Left = Forward button), and so intuitive once you learn to use it. Being able to build custom searches (visit any site with a search box, right click it and you can search it from your address bar).
Firefox has addons that incorporate a lot of these features, like Fast Dial if you like Opera’s Speed Dial, but these are third party and don’t always mesh as well and make FF slow and Crash Prone.
Written by udkl on 01.07.09
OH my GOD, THANKS! I gained a quarter inch of screen space back, so now my address bar can display another 5 characters. MUCH NEEDED MOD, i dunno how i could even stand to USE the internets before!
THX AGAIN!
Written by Fat on 02.06.09