User Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:51.0) Gecko/20100101 Firefox/51.0 Build ID: 20170125094131 Steps to reproduce: UI glitching: I can't say I do anything special to make a Firefox UI glitch: I just open a youtube video, maybe change a tab or two and it happens. I can say I'm able to reproduce it quite easily. Browser crashing: I made Firefox reliably crash several times in a row by opening a youtube video and a few reddit pages in quick succession, so they're loading at the same time, but I haven't managed to make it crash every time. I know it's not terribly specific, but that's what it takes for it to crash. I think a key point to what makes it crash is that I load multiple pages at once. UI glitches from previous paragraph don't cause Firefox to crash, I can use it while it's looking like that. Actual results: UI glitching: text in Firefox UI isn't displaying what it should, writing text displays wrong text etc. I included what glitches look like in pictures 1, 2 and 3.

Hello, I just created a Bugzilla account, so I apologize if I make some mistakes. Here are crash reports: bp-44892ae6-e42e-41cc-82b6-5d15a2170127 27.1.2017 17:35 bp-6124ccda-8b46-4642-adba-c10e32170127 27.1.2017 17:35 bp-63262f09-cb1b-4eba-914b-133152170127 27.1.2017 17:34 bp-bb7402cd-918c-4fb8-9b2f-f3f302170127 27.1.2017 17:31 bp-19f89a12-8c7a-42c4-92c5-2ed732170127 27.1.2017 17:30 bp-f481ff16-9129-4e8f-a703-6f3302170127 27.1.2017 16:31 bp-7256c6ec-db29-4a40-b0e9-c82d02170125 25.1.2017 8:27 bp-fbdd3767-ab42-4e23-93cc-39bca2170124 24.1.2017 20:58 bp-ddc9e9d3-b388-4b53-bea9-03f8e2170124 24.1.2017 20:56 eaea0ceb-5c7b-43aa-b2f5-2ad096ef81e6 24.1.2017 19:50 (this one says throttling) bp-5d41ec2f-4f0a-47ed-83d6-63f6a2170124 24.1.2017 19:31 bp-fa7bf737-609a-4382-ac76-3f9372170124 24.1.2017 19:30 I refreshed my profile and reinstalled Firefox, butissues kept happening. Only after disabling hardware acceleration did they disappear. I haven't been able to reproduce any problems in safe mode, with hardware acceleration both on and off. I manually disabled all add-ons and with hardware acceleration on, UI glitched and Firefox crashed. Maybe there's no reason for me to write this bug report as I've managed to "fix" my issues, but I figured it might be a good idea to bring it to your attention.

As for the UI & text glitches, this bug seems similiar to Bug 1334748.

Another similiar issue: Bug 1334778.

Another similiar one: Bug 1334830 (it is possible that FF 51+ is visually broken)

marcino245, could you stop cross posting links over and over on all bug reports with graphics issues. Some of these bugs are about AppArmor on Linux, others are about HWA/drivers on Windows.

I too, since I upgraded to version 51, present problems with UI glitch (but no crash). The phrases appear only if they are selected using the mouse: example http://imgur.com/a/n4WjZ The problem goes away if I disable the hardware acceleration.

The add-on that I used as the test is called "Add-on Compatibility Reporter"