Steps to reproduce: 1. about:config 2. webgl.angle.try-d3d11 -> FALSE 3. http://get.webgl.org/ Expected Results: See a rotating 3D object Actual Results: FF 43.x -> Correct FF 46.0a1 (2016-01-11) -> Hmm. While your browser seems to support WebGL, it is disabled or unavailable. If possible, please ensure that you are running the latest drivers for your video card. I noticed this issue with both my laptop w/ Intel HD 4000 and desktop w/ Nvidia 650 GTX. This important to fix because older hardware like my laptop w/ X1300 do not support D3D11.
WebGL is now working again on Nightly. Thank you. Tested on 47.0a1 (2016-02-03)