A Few Tips for Using Firefox 40 with Windows 10

Mozilla’s recently-released Firefox 40 looks great on Windows 10, but it also offers some compelling advantages over Microsoft Edge and Google Chrome. If you are going to use Firefox on Windows 10, here are some tips for making it work well in this new OS.

Set Firefox as the default web browser

I mentioned this in Firefox 40 is Designed for Windows 10, but it bears repeating: While you can use Settings to configure Firefox as your default web browser (navigate to Settings, System, Default Apps), to fully configure Firefox for all possible defaults, you will need to use the Set Default Programs control panel, which is accessible via the Set defaults by app” link. In the Set Default Programs control panel window that opens, select the application in the list and then select “Set the program as the default.”

Use your default Firefox search engine with Cortana or Windows

I was intrigued by Mozilla’s note that Firefox users could use their default browser search as their search default in Windows too. This means that when you search with Cortana—or, if Cortana is not available, Windows Search—the web results will be delivered via your preferred search engine (Google, most likely) and not Bing.

This is automatic if you configure Firefox as your default browser. But if you don’t want this behavior—i.e. would still like to use Bing with Cortana for some reason—you can disable it. In Firefox, open Options and navigate to Search. Then, uncheck the option “Use this search engine for searches from Windows.” Neat.

Enable tab previews

Former Internet Explorer users—there must be a support group somewhere—know that one of that browser’s neatest features is the ability to display tab previews: when you mouse-over the IE taskbar button, you see previews for each open tab instead of a single preview (as with Edge or Chrome) of the currently-selected tab only.

Firefox works like Edge and Chrome by default, but you can enable tab previews in Options, General. Just select “Show tab previews in the Windows taskbar.”

Make Firefox work better on high-DPI displays

One of the biggest problems with Windows web browsers is that they all handle high-DPI displays—like the Quad HD+ (3200 x 1800) wonder on the Dell XPS 13—differently, and usually poorly. Chrome is borderline broken on such displays (regardless of platform, this is true in Chrome OS too), and while Edge actually does work well in this regard, it’s missing so much other functionality I can’t really use. But Firefox has a hidden scaling feature that makes it sing on any high-DPI display, and should make this browser usable for anyone on any device.

Here’s the trick. You need to access Firefox’s secret advanced settings list and change the value of a single setting. To do so, type about:config in the Firefox address bar and click past the tongue-in-cheek “This might void your warranty” warning. Then, in the Search box (the advanced settings Search box, not the one in the browser toolbar), type layout.css.devPixelsPerPx. This is set to -1 by default.

Try changing to different values in .25 increments. I found that 1.25 works best for my eyes on my laptop, but you may prefer a different value.

And take advantages of the normal Firefox features

Beyond these Windows 10-specific things, be sure to check out all that makes Firefox special, like its add-on infrastructure (start with AdBlock Plus), themes (though I like the default Windows 10 theme personally) and amazing customization capabilities, especially around the toolbar. Firefox is possibly the most easily and fully customizable browser available.