If you’ve been paying attention, you know that the Firefox browser has made serious headway to reclaiming its user base. In fact, the open source browser has not only succeeded with that task, it’s gone so far as to become one of the best browsers on the market (if not the best browser). There are many reasons for this. One of the lesser-known reasons is the Test Pilot program. Test Pilot allows users to test out new features for the browser and then for Mozilla to decide (based on metrics from each experiment) what features should be rolled into the browser.

One of the more recent additions to Test Pilot is Side View. With this mode users can view two sites (at the same time) within one browser window. But it’s more than that. With Side View on, you can adjust the size each window gets (to a point … more on that in a bit). With that in mind, you can do things like keep a side-bar-like Twitter open, while working in another window. Or view a YouTube video while doing your work. This project makes for an outstanding (and efficient experience in Firefox). I want to walk you through the process of installing and using Side View in Firefox.


Obviously you’ll need Firefox. You’ll need a recent release of the browser that supports the Test Pilot extension. The good news is that the developers have made it very easy to install both Test Pilot and Side View together. Point your browser to the Side View Test Pilot page. Click on the Install Test Pilot & Enable Side View button (Figure A).

Figure A

When prompted, click the Add button. Once Test Pilot has installed, you’ll be asked to enter an optional email address (to find out about new experiments and see the results of experiments you’ve tried). Once you’ve taken care of that, you will be prompted to click Add to enable Side View. Do that and the Side View experiment will be added to your Firefox browser. You’re ready to go.


Using Side View is quite simple. You’ll notice a new icon in your main toolbar (located to the right of the address bar). If you click that icon, a drop-down will appear with a list of recent sites and current tabs (Figure B).

Figure B

Select one of those sites and the chosen page will open in the left sidebar of the browser. With the two pages open side by side (Figure C), you can then drag the separator to give the left window more space.

Figure C

The one caveat is that, with certain pages, you can only give that left pane a certain amount of space. I found with some sites at around 25% of the full window size, the drag bar stops. That means whatever page you have in the right pane will always hold about 75% of the browser window real estate. Because of this, you’ll want to make sure the sites you add to the left pane are viewable at around 25%. This doesn’t happen with every site, so your mileage may vary. However, with every site, you cannot extend the Side View beyond 50% of the screen real estate.

Personally, I have found Side View a great way to have a Twitter feed open at all times, without having to switch between tabs. So if you have a site you frequently check (one that doesn’t need a lot of window space), Side View might be the ideal solution.

Once you have the window sized exactly how you like it, you’re ready to view those to pages in Side View mode. When you’re done, you can either click the X in the upper right corner of the left pane to close the window, or you can select Bookmarks from the upper left drop-down to view the Bookmark sidebar. Of course, if you opt to go the bookmark route, you’ll want to resize that window such that it is sidebar size.

One you go Side View…

It took me maybe thirty seconds to become attached to the new Side View experiment. It is my hopes that this Test Pilot venture will eventually make its way into the standard Firefox feature set. It’s that useful. Give Side View a try, and see if you don’t wind up dependent upon this one-trick pony.