On my laptop with the specs Windows 7 Home Premium 64-bit Intel(R) Core(TM) i5-2557M CPU @ 1.70GHz (4 CPUs), ~1.7GHz 4096MB RAM Intel(R) HD Graphics 3000 Intel(R) GPU driver version 9.17.10.2932 Intel(R) GPU driver date 12/14/2012 (up-to-date) running https://www.khronos.org/registry/webgl/sdk/tests/conformance/rendering/gl-scissor-test.html with both Firefox 24 stable and Firefox 27.0a1 Nightly (2013-10-17) gives output: Check if glScissor setting works. On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". Canvas.getContext test antialias: false PASS context exists test with clear checking rect: effective width or heigh is zero PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green checking rect: effective width or heigh is zero PASS should be black test with draw checking rect: effective width or heigh is zero PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green checking rect: effective width or heigh is zero PASS should be black PASS getError was expected value: NO_ERROR : there should be no errors test antialias: true PASS context exists test with clear checking rect: effective width or heigh is zero PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green PASS should be black PASS should be black PASS should be green checking rect: effective width or heigh is zero PASS should be black test with draw checking rect: effective width or heigh is zero PASS should be black PASS should be green FAIL should be black at (1, 0) expected: 0,0,0,0 was 0,255,0,255 FAIL should be black at (0, 1) expected: 0,0,0,0 was 0,255,0,255 PASS should be green PASS should be black PASS should be black PASS should be green FAIL should be black at (3, 2) expected: 0,0,0,0 was 0,255,0,255 FAIL should be black at (2, 3) expected: 0,0,0,0 was 0,255,0,255 PASS should be green PASS should be black PASS should be black PASS should be green FAIL should be black at (5, 4) expected: 0,0,0,0 was 0,255,0,255 FAIL should be black at (4, 5) expected: 0,0,0,0 was 0,255,0,255 PASS should be green PASS should be black PASS should be black PASS should be green FAIL should be black at (7, 6) expected: 0,0,0,0 was 0,255,0,255 FAIL should be black at (6, 7) expected: 0,0,0,0 was 0,255,0,255 PASS should be green PASS should be black PASS should be black PASS should be green FAIL should be black at (9, 8) expected: 0,0,0,0 was 0,255,0,255 FAIL should be black at (8, 9) expected: 0,0,0,0 was 0,255,0,255 PASS should be green PASS should be black PASS should be black PASS should be green FAIL should be black at (11, 10) expected: 0,0,0,0 was 0,255,0,255 FAIL should be black at (10, 11) expected: 0,0,0,0 was 0,255,0,255 PASS should be green PASS should be black PASS should be black PASS should be green FAIL should be black at (13, 12) expected: 0,0,0,0 was 0,255,0,255 FAIL should be black at (12, 13) expected: 0,0,0,0 was 0,255,0,255 PASS should be green PASS should be black PASS should be black PASS should be green FAIL should be black at (15, 14) expected: 0,0,0,0 was 0,255,0,255 FAIL should be black at (14, 15) expected: 0,0,0,0 was 0,255,0,255 PASS should be green checking rect: effective width or heigh is zero PASS should be black PASS getError was expected value: NO_ERROR : there should be no errors PASS successfullyParsed is true TEST COMPLETE

@Jukka Jylänki On Linux this test is passing. Can you verify that it's still failing under Windows?

Nightly 39.0a1 (2015-03-25) Win7 - Intel HD3000 - D2D1.1 - D3D (OMTC) - WebGL Renderer Google Inc. -- ANGLE (Intel(R) HD Graphics 3000 Direct3D11 vs_4_1 ps_4_1) I still see exactly the same problems Jukka Jylänki reported

Reconfirmed that the failure occurs on the same hardware configuration that the initial comment 0 was from: MACBOOK_AIR_WIN --------------- MacBook Air (13-inch, Mid 2011) Windows 7 Home Premium 64-bit in dual-boot mode (bootcamp) 1.7GHz Intel Core i5 4GB 1333 MHz DDR3 1440x900 pixels display Intel HD Graphics 3000 384MB - Vendor: Intel (0x8086) - Device ID: 0x0116 - Revision ID: 0x0009 System DirectX version: DirectX 11.0 Intel HD Graphics 3000: - igdumd64.dll, igd10umd64.dll: - version 9.17.10.3517 - date 3/20/2014 - DDI Version 10.1, WDDM 1.1, WHQL approved Firefox Nightly 41.0a1 (2015-06-29)

The failure did not occur on any of the following: SPARK, GIADA, MACBOOK_AIR_OSX, MACBOOK_PRO_OSX, MACBOOK_PRO_WIN, MACMINI, MACPRO, NEXUS-4, NEXUS-5, NEXUS-10, SURFACE, WINDBOX, HASWELL, HPOMEN (see https://bugzilla.mozilla.org/show_bug.cgi?id=1178601 for hardware configuration details of these systems)

Retested to fail on - Samsung Galaxy S4 GT-I9500 - Android 5.0.1, Kernel 3.4.5-5676501, Fennec 55.0a1 (2017-05-19) - Imagination PowerVR SGX 544MP, OpenGL ES 2.0 build 1.10@2359475 - Apple MacBook Air 13" Mid-2011 - macOS Sierra 10.12.3 - Firefox 55.0a1 (2017-05-22) (64-bit) - Intel HD Graphics 3000 2.1 INTEL-10.2.12 but passes on - Apple MacBook Pro 13" 2016 - macOS Sierra 10.12.3 - Firefox Nightly 55.0a1 (2017-05-21) (64-bit) - Intel Iris Graphics 550 1536 MB 4.1 INTEL-10.22.29 - Apple Mac Mini (Late 2012) - Ubuntu 16.04 Xenial, Kernel 4.4.0-78-generic 64-bit - Firefox 55.0a1 (2017-05-22) (64-bit) - Intel HD Graphics 4000, Intel Mesa DRI Ivybridge Mobile, OpenGL 3.3 (Core Profile) Mesa 12.0.6 - Apple Mac Pro (Late 2013) - OS X El Capitan 10.11.6 - Firefox 55.0a1 (2017-05-22) (64-bit) - AMD FirePro D500 4.1 ATI-1.42.15 - HP Notebook 14-am009no 14" - Windows 10 Home - Firefox 55.0a1 (2017-05-22) (64-bit) - Intel HD Graphics (Intel HD 400?) Direct3D 11, 20.19.15.4509 9-1-2016, OpenGL ES 3.0 (ANGLE 2.1.0.dec065540d5f) - Haswell - Windows 10 Home 64-bit - Firefox 55.0a1 (2017-05-22) (64-bit) - 2x ASUS NVidia GeForce GTX 1080 Ti Direct3D 11, v22.21.13.8189 (4-19-2017), OpenGL ES 3.0 (ANGLE 2.1.0.dec065540d5f) - Intel NUC6i7KYB Skull Canyon - Windows 10 Pro 10.0.14393 64-bit, Firefox 55.0a1 (2017-05-22) (64-bit) - Intel Iris Pro Graphics 580, 21.20.16.4534 (10-7-2016), OpenGL ES 3.0 (ANGLE 2.1.0.dec065540d5f) - Supermicro X10DAX 1.02 - Linux Mint 18 Sarah, Kernel 4.4.0-36-generic 64-bit, Firefox 55.0a1 (2017-05-22) (64-bit) - ASUS GeForce GTX 1060 OpenGL 3.2.0, NVIDIA 370.28 - Microsoft Surface Pro 2 - Windows 10 Pro, Firefox 55.0a1 (2017-05-22) (64-bit) - Intel HD Graphics 4400 Direct3D11 v20.19.15.4331 (11-18-2015), OpenGL ES 3.0 (ANGLE 2.1.0.dec065540d5f) - LG Nexus 5 - Android 6.0.1, Kernel 3.4.0-gcf10b7e (hammerhead M4B30Z), Fennec 55.0a1 (2017-05-19) - Qualcomm Adreno 330, OpenGL ES 3.0 V@127.9 AU@(GIT@I98aee987eb) - Google Pixel XL - Android 7.1.2, Kernel 3.18.31-g416bf43 (marlin N2G47O), Fennec 55.0a1 (2017-05-19) - Qualcomm Adreno 530, OpenGL ES 3.2 V@145.0 (GIT@Idb2b4cb785) - Samsung Galaxy S7 Edge SM-G935F - Android 7.0, Kernel 3.18.14-11104523 (NRD90M), Fennec 55.0a1 (2017-05-19), ARM Mali-T880, OpenGL ES 3.2 v1.r12p1-03dev0.228ab63cced004f840e7dd47b762a1d0 - Huawei P10 Plus - Android 7.0, Kernel 4.1.18-gfd75bbb (VKY-L29), Fennec 55.0a1 (2017-05-19) - ARM Mali-G71, OpenGL ES 3.2 v1.r2p0-02dev0.f7269486f3e0e3b308edf85872e361f4 - LG Nexus 4 - Android 5.1.1 Kernel 3.4.0-perf-gdffc258 (occam LMY48T), Fennec 55.0a1 (2017-05-19) - Qualcomm Adreno 320, OpenGL ES 3.0 V@104.0 AU@ (GIT@Id3510ff6dc) (no WebGL 2, missing standard_derivatives) - Samsung Nexus 10 - Android 5.1.1 Kernel 3.4.67-g84ad5a4 (mantaray LMY49J), Fennec 55.0a1 (2017-05-19) - ARM Mali-T604, OpenGL ES 3.1 (no WebGL2 because of lack of renderbuffer_color_float & renderbuffer_color_half_float)