Firefox 10 and Firefox ESR 10 were released on January 31, 2012.[31][32] Firefox 10 added a full screen API and improved WebGL performance, support for CSS 3D Transforms and for anti-aliasing in the WebGL standard for hardware-accelerated 3D graphics. These WebGL updates mean that more complex site and Web app animations can render smoothly in Firefox, and that developers can animate 2D objects into 3D without plug-ins.[33][34] It also introduced a new CSS Style Inspector, which allow users to check out a site's structure and edit the CSS without leaving the browser.[31] Firefox 10 assumed all add-ons made for at least Firefox 4 were compatible. 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.[35]