User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_6_3; en-us) AppleWebKit/533.16 (KHTML, like Gecko) Version/5.0 Safari/533.16 Build Identifier: 1.9.2 the java api in xpcom.jar's is platform dependend and differ. See difference here http://blog.yahor.net/2010/06/system-specific-interfaces-in-xulrunner.html So Any ideas why it happened? Reproducible: Always Steps to Reproduce: 1.Compare xpcom.jar from xulruner-sdk 2. 3.
The interfaces in question are only built on platforms which use them: at least in the build you are using, mac didn't build with accessibility until quite recently, and the windows-specific interfaces (nsITaskbar*) are not built on the other platforms. If you need to use these, you should probably combine the JARs from multiple platforms, or something. I doubt this is something we will fix within the Mozilla code.