The latest Firefox Nightly release makes it easier to test vertical tabs and the browser's new sidebar.

Mozilla launched support for the, much requested, vertical tabs feature in Firefox in June. Back then, it was necessary to flip several configuration switches manually to unlock the functionality.

Today's Nightly update changes this. Now, vertical tabs and sidebar can be enabled in the browser's settings. This exposes the feature to more testers and makes it easier to manage it.

Vertical Tabs arrive in Firefox Nightly's Settings

Here is how that is done:

1. Load about:preferences#experimental in the browser's address bar.
   1. If you prefer to go there manually, go to Home > Settings > Firefox Labs.
2. Check Vertical Tabs to enable the feature in Firefox.

Note: while you can enable Sidebar individually, enabling Vertical Tabs will always enable the Sidebar as well. The reason is simple: vertical tabs require the sidebar.

Vertical tabs are enabled automatically at this point. Tabs show up as favicons. You can hover over a tab to display its title and other information. You can use the customize toolbars option to drag the new sidebar icon to the toolbar.

Activation of it toggles between the full display of tabs in the sidebar and the favicon-only display.

The current iteration displays tabs only on the sidebar, but the original horizontal bar remains. There does not seem to be an option to turn this off entirely at this point.

A click on the settings icon displays a few options. You can move tabs and the sidebar to the right, if you prefer that position. Other options include auto-hiding the sidebar and toggling the visibility of Firefox Tools on the sidebar.

The four tools Chatbot, Tabs from other devices, History, and Bookmarks, can be toggled individually.

Some features work already:

• Right-click on a tab to get the full context menu. This gives you all tab-based options, including bookmarking, reloading, closing, muting, and many more.
• Drag & drop tabs to change the order. This works on a single window but also multiple windows.

The basic functionality is there already. The current iteration lacks features that made Tab Mix Plus great. This includes support for displaying different levels, configuring tab opening and merging behavior, and more.

Whether any of that is coming in a future release remains to be seen. For now, I'd be happy with an option to reduce the size of the titlebar when tabs are displayed on the side.

Closing Words

Work on vertical tabs continues. Mozilla has not announced a release date for the feature. Good news is that this feature is completely optional. If you prefer a horizontal placement, you will be able to continue using Firefox as before.

For users who swear on vertical tabs, as they may allow you to squeeze more tabs on the screen with larger titles than horizontal tabs, it is a going to be a welcome feature.

Now You: do you prefer vertical or horizontal tabs? Any specific reason for that? Let us know in the comments below.