I recently downloaded the latest version of Firefox. I quickly discovered that one of my favourite features was gone: the ability to close a tab if it’s the only one open.

It’s turns out that the feature isn’t missing; it’s just no longer enabled by default. I figure this makes sense since a fresh install of Firefox doesn’t show the tab bar at all for a single tab.

Anyway, here’s how to do it, just so you don’t have to mess around with the options to figure it out (like I did):

  1. Open about:config.
  2. Set browser.tabs.closeWindowWithLastTab to false.

And that’s all! Back to “normal” browsing.

EDIT: Looks like I beat mozillaZine by about 4 minutes on this. They now have a longish thread discussing this exact topic.