in Firefox, however Internet Explorer 7's quirks mode does not either. CNET notes that Firefox does not support ActiveX controls by default, which can also cause webpages to be missing features or to not work at all in Firefox. Mozilla made the decision to not support ActiveX due to potential security vulnerabilities, its proprietary nature and its lack of cross-platform compatibility. There are methods of using ActiveX in Firefox such as via third-party plugins but they do not work in all versions of Firefox or on all platforms. Beginning on December 8, 2006, Firefox Nightly builds pass the Acid2 CSS standards compliance test, so all future releases of Firefox 3 would pass the test. Firefox also implements a proprietary protocol from Google called "safebrowsing", which is not an open standard. Cross-platform support Mozilla Firefox runs on certain platforms that coincide OS versions in use at the time of release. In 2004 version 1 supported older operating systems such as Windows 95 and Mac OS X 10.1, by 2008 version 3 required at least OS X 10.4 and even Windows 98 support ended. Various releases available on the primary distribution site can support the following operating systems, although not always the latest Firefox version. Various versions of Microsoft Windows, including 98, 98SE, ME, NT 4.0, 2000, XP, Server 2003, Vista, 7, 8 and 10. OS X Linux-based operating systems using X.Org Server or XFree86 Builds for Solaris (x86 and SPARC), contributed by the Sun Beijing Desktop Team, are available on the Mozilla web site. Mozilla Firefox 1.x installation on Windows 95 requires a few additional steps. Since Firefox is open source and Mozilla actively develops a platform independent abstraction for its graphical front end, it can also be compiled and run on a variety of other architectures and operating systems. Thus, Firefox is also available for many other systems. This includes OS/2, AIX, and FreeBSD. Builds for Windows XP Professional x64 Edition are also available. Mozilla Firefox is also the browser of choice for a good number of smaller operating systems, such as SkyOS and ZETA. Firefox uses the same profile format on the different platforms, so a profile may be used on multiple platforms, if all of the platforms can access the same profile; this includes, for example, profiles stored on an NTFS (via FUSE) or FAT32 partition accessible from both Windows and Linux, or on a USB flash drive.