User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b9pre) Gecko/20101229 Firefox/4.0b9pre Build Identifier: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b9pre) Gecko/20101229 Firefox/4.0b9pre Microsoft's performace demo is rendered differently in FFX, cloned elements having their own gradients are not applying them to the elements. I tried to discover why for a while, but failed (sorry, this bugreport is really not well prepared, but I'm ill with high temperatures and thus results of my work are not good :-( ) All snowflakes, some tree branches and elf bodies are filled with black instead of with gradient, for example fills using those IDs: url(#snowCoveredTreeId_10_), url(#skyGradient1), url(#redelfid_1_) and many others. I do not see way how the demo is created/is working proper, I consider it abuse of SVG, rather then USE (e.g. increasingly adding rotate transformations to snowflakes again and again), but many people are paying BIG attention to all M$ perfdemos. Problem is not with static rendering, see attachment, but with dynamic multiplication of the elements with their own gradients... Again, sorry for the low quality of the bugreport, but I'm in no condition... Reproducible: Always Steps to Reproduce: Open URL and watch Actual Results: Snow flakes, some tree branches and elves bodies are filled black Expected Results: Should be filled with colorful gradients..

They have used display:none rather than use defs elements.