Unveiling Tab Previews: A New Feature in Progress by Firefox Developers

Tab previews are being prepared for a forthcoming iteration of Mozilla Firefox.

At present, in Firefox versions, you position your cursor over a non-active tab (essentially, any tab that you’re not currently looking at) to see a tooltip that includes the webpage title after a brief pause.

This is quite useful, particularly if you have a large number of tabs open, several of which are from the same website, and you cannot see enough of the page title in the tab itself to identify which page it is.

However, Mozilla developers are testing a major improvement in the form of tab previews in the newest Firefox beta versions.

When this feature is enabled, tab tooltips adopt a new ‘card’ design that shows a large thumbnail preview of each webpage, the website/webpage title, and the page URL:

Preview Link

Top: default tooltips; bottom: tab previews enabled

Firefox’s tab previews work with every tab except from the current/active one, including pinned tabs (where this feature could prove particularly useful given they only show a favicon).

As this flag/switch is not enabled by default in current Firefox beta builds we shouldn’t expect to find tab previews in Firefox 123 when it’s released as a stable update later this month.

But the fact Firefox devs are working on this feature is encouraging.

Other modern web browsers, including Google Chrome, Vivaldi, and Safari (though that’s not available on Linux) also show thumbnail previews when users mouse over non-active browser tabs.

It’s understandable that Firefox would wish to follow suit.

That said, some folks find these visually-rich tooltips distracting, so I hope Mozilla choose to include a toggle to disable tab previews in Firefox if — and for now it is still an ‘if’ — it decides to enable them by default in a future release.

Enable Tab Previews in Firefox 123 Beta

To try this out you need to set this switch to ‘true’

To try this experimental feature you need to have the latest beta build of Mozilla Firefox.

If you’re on Ubuntu you can install Firefox beta from Mozilla’s APT repo, download a binary from the Firefox website, or use the beta channel in the Snap Store.

Begin by opening Firefox Beta, then follow these steps:

  • Navigate to about:config in a fresh tab.
  • Look for the browser.tabs.cardPreview.enabled flag.
  • Double-tap on the line in order to set it to true. If there’s an icon at the end of the line, you may click on it.

Once it’s activated, it’s ready to be used, there’s no need for a browser restart.

If you’d rather not have web page thumbnails appear in the new tab cards, you have the option to disable them by flipping the browser.tabs.cardPreview.showThumbnails switch to false.

To control how fast/slow tooltips appear modify browser.tabs.cardPreview.delayMs. This is set to 1000 (milliseconds) by default, meaning tooltips only appear once you’ve hovered over a tab for at least a second.

via soeren-hentzschel.at