User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:64.0) Gecko/20100101 Firefox/64.0 Steps to reproduce: try this page, https://devnook.github.io/OffscreenCanvasDemo/keep-ui-responsive.html after enable offscreen cavas in about:config, this page still can't be rendered. Actual results: on the page, the offscreen canvas is rendered as blank Expected results: offscreen canvas should work if enabled

the same page works fine in chrome

NS_ERROR_NOT_IMPLEMENTED: animation.js:74 set theme https://devnook.github.io/OffscreenCanvasDemo/animation.js:74:45 ThemedAnimation https://devnook.github.io/OffscreenCanvasDemo/animation.js:69:5 <anonymous> https://devnook.github.io/OffscreenCanvasDemo/keep-ui-responsive.html:120:31 <anonymous> https://devnook.github.io/OffscreenCanvasDemo/keep-ui-responsive.html:105:5 duplication of bug 801176?

I realized that not only offscreencanvas doesn't work on my machine, webgl doesn't work at all. I checked about:support, firefox can detect my nvidia 1080ti gpu, and I have webgl working fine under chrome. I searched, someone said this might be a bug in nvidia driver, if firefox is launched with sudo, the issue will be gone. I tried, but I wasn't able to start firefox with sudo, I saw errors with Mir. another error message I saw with the terminal was libGL.so can't find the right fbconfig or something. I'm using ubuntu 17 with firefox 64/61.