Firefox 10 and Firefox 10ESR were released on January 31, 2012. It is the first official extended support release. Firefox 10 hides the forward arrow button until there is a website to go forward to, or it is manually activated.[72] Firefox 10 adds a Full Screen API and improved WebGL performance.[73]
Firefox 10 assumed all add-ons were compatible with version 10, as long as they are written for at least Firefox 4. The add-on developer is able to alert Mozilla that the add-on is incompatible, overriding compatibility with version 10 or later. This new rule also does not apply to themes.[74]
Firefox 10 added the CSS Style Inspector to the Page Inspector, which allow users to check out a site's structure and edit the CSS without leaving the browser.[75]
Firefox 10 added support for CSS 3D Transforms and for anti-aliasing in the WebGL standard for hardware-accelerated 3D graphics. These updates mean that complex site and Web app animations will render more smoothly in Firefox, and that developers can animate 2D objects into 3D without plug-ins.[73]