User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:2.0) Gecko/20100101 Firefox/4.0 Build Identifier: Mozilla/5.0 (Windows NT 5.1; rv:2.0) Gecko/20100101 Firefox/4.0 I can not put this another way; Its about time this gets fixed. Firefox supports web standards fairly well and this leaves a bit of a hole in its otherwise good reputation comparative to a whole range of other browsers. Firefox does admittedly come very close to passing so we should consider closing this gap up promptly. Kind Regards, Reproducible: Always Steps to Reproduce: 1. Head over to http://acid3.acidtests.org/ 2. 3. Actual Results: 97/100 Expected Results: 100/100 Chrome, Opera, Safari and any other Webkit Browser is able to pass with 100% for some time now. IE9 can even pass with 95/100 now too!

verified dupe Gecko will probably never reach 100% http://limi.net/articles/firefox-acid3/