Web content is no longer accessible to screen readers in Tor Browser for Windows

Summary

Web content is no longer accessible to screen readers on Windows. One can tab through elements in the focus order, but cannot read the document or non-focusable elements fully as in previous versions or other web browsers like Firefox.

Steps to reproduce:

1. Open Tor Browser with a screen reader, such as NVDA, running.
2. Try to browse any website (not internal firefox tabs such as about:config) in "Browse Mode" using the arrow or document navigation commands.
3. ... The document will not be read, only focusable elements when tabbing through them, no matter if "focus" or "browse" mode is enabled.

What is the current bug behavior?

Web content is not accessible to screen readers.

What is the expected behavior?

Web content should be accessible to screen readers as in previous releases, not just focusable elements.

Environment

OS: Windows 10

Installation method: Update from previous version, also tried installing the latest alpha with no fix.

Tor Browser Version: 12.0.4

Relevant logs and/or screenshots

changed the description

What was the last Tor Browser version on Windows where it worked?

One of the first debugging questions will be: did Firefox break this with their update, or did some new Tor Browser change break it? To get started there, is it possible for you to test Firefox 102.9esr and see if it has this problem too?

@richard thanks for following up!:) The official released ESR build works as it should. However, both Tor Browser and one of the mingw builds I tested from the link above fails to present web content accessibly.

@tom hey where can we get esr102 and rapid-release mingw builds off of phabricator?

On treeherder, in the upper right, you choose 'Repos' to select esr102. You can put 'mingw build' in the search box to filter: https://treeherder.mozilla.org/jobs?repo=mozilla-esr102&searchStr=mingw%2Cbuild

@Malthej can you compare the behaviour of one of the above firefox mingw esr102 builds with tor browser and firefox official published esr102?

Mozilla ships builds built with Microsoft's MSVC toolchain while we ship builds built with the open souce mingw toolchain. However, they are nice enough to also build mingw Firefox builds as well to our benefit :)

Hello; I'm a Blind user of Tor about years. So I discovered this topic, make my on tests and the problem is on accessibility.cache.enabled was disabled by default in tor at about:config. Turning it on bring back the normal html rendering and accessibility works again.

Mai by it need to be turned on on the next releases.

ESR115 uses CTW (cache the world) and is on by default. IDK why accessibility.cache.enabled is false in Tor Browser and I don't think it makes any difference in ESR115, so we should at least work out why it was disabled and if it still applies and if so, if it still works. I lack any disability tools to test

^ for example 1821955 [CTW] Enable the cache regardless of the pref

@jonassmarques I'm so glad you came to report this. I'm about to publish Tor Browser Alpha 12.5a7 which is the release candidate for the 12.5 release in a few weeks. Once it's up (I'll ping you again) can you flip the pref and verify things work as expected?

@jonassmarques I spoke too soon and actually the installers are already published:

• windows x86 (32-bit): https://dist.torproject.org/torbrowser/12.5a7/torbrowser-install-12.5a7_ALL.exe
• windows x86_64 (64-bit): https://dist.torproject.org/torbrowser/12.5a7/torbrowser-install-win64-12.5a7_ALL.exe

Can you verify enabling the accessibility.cache.enabled pref fixes this issue for you?

@richard Sorry, on installers who you send the accessibility.cache.enabled was turned off by default.

When enabled It, it worked perfectly.

I Tried Using NVDA Screen Reader, Win 11 Narrator and worked on both.

@thorin If you are on Win 10 or 11 you can Just press Win key + Enter to enable narrator, and it work on every web rendering engine. And also, if you want, NVDA is a free Screen Reader who can be used to that.

Ok that's great, we'll make sure pref is flipped for the next releases!

@jonassmarques I do actually now, finally since the last 2 months, have a win 10 (upgraded to 11) machine so thanks for the info on how to trigger it (I've never used it before)

@richard why was it flipped off? there must be an old ticket with reasons

^ ahh, I know why

• FF90+ 1710976 Add a pref for Cache the World, default false
• FF113+ 1824293, 1824295 flip it on

IDK why ESR102, which is still default false, would affect us but not FF (or maybe it does?). Anyway, it is enabled for ESR115, so this wasn't something we disabled on purpose

for the record ... accessibility.cache.enabled was removed in FF115 1821955 part 6

meanwhile: alpha 12.0.7a has the pref as false, but stable 12.5.1 has it as true, which seems at odds

We had intended to enable for 12.5a7 but missed it so enabled it in 12.5.

added Accessibility Bug Windows labels

added Backlog label

I accidentally edited a comment above, my apologies. For continuity purposes, here's my new comment below again: @richard thanks for following up!:) The official released ESR build works as it should. However, both Tor Browser and one of the mingw builds I tested from the link above fails to present web content accessibly.

@Malthej what if you update security.sandbox.content.level to 0 in about:config? If this works, can you identify at which level accessing the content breaks?

@richard Unfortunately web content still fails to display properly when "security.sandbox.content.level" is set to 0 in Tor Browser.

added 12.5 stable label

assigned to @pierov

@pierov 12.5a7 seems to work fine already for me

Maybe it was a temporary thing broken on Moz's side and then fixed in a 102.x update. We should check Bugzilla.

@henry can you try to bisect our alphas and see when it fixed itself?

https://archive.torproject.org/tor-package-archive/torbrowser/

Testing with windows 10 virtual machine, NVDA 2022.3.2 and loading example.org, I can browse the web page no problem (reading the page, browsing with up and down arrows and reading each line) on:

• 12.0 (102.5.0esr),
• 12.0.3 (102.8esr)
• 12.0.4 (102.9.0esr)
• Upgrading from 12.0.3 to 12.0.7 (102.12.0esr)
• 12.0a1 en-US (91.12.0esr),
• 12.5a1 (102.6.0esr),
• 12.5a7

So I'm not sure I'm able to reproduce the original issue at all with my set up.

I also upgraded to NVDA 2023.1 and checked 12.0 and 12.5a7 and it was the same.

For those two versions, I also verified that accessibility.cache.enabled was indeed false.

The new cache is meant to help performance, so it could have been hardware related. I'm not sure.

Hi Guys:

as I'm following the discussion I decided to do my next tests.

Any version since 12.0 does not automatically work with NVDA. I even tested the 12.07 alpha version and it also doesn't work without enabling the cache option.

• DEBUG: OS: Windows 11 10.0.22621.1848 NVDA: 2023.1 Tor version: Any after 12.0

Tab Key not Work, arrow keys not work, modifier keys not work, interaction controls do not work att all. Just menu bars and other non rendered components work's.

Hi @jonassmarques, could you please check with:

• https://tb-build-05.torproject.org/~richard/builds/torbrowser/release/unsigned/12.5.0-build1/ (candidate for the release)
• https://people.torproject.org/~pierov/tmp/torbrowser-install-win64-12.5rc-screenreader.exe (candidate + pref already set)

Thanks!

Hello;

Tried the two versions, both no work. And in (candidate + pref already set) the acessibility.cache was disabled. When enabled it works, but on fresh install it comes disabled.

Oops, you're right. My bad, I set the hash in the wrong place in the build config, let me run another build.

Fixed, I've uploaded a new build at the same address.

Okay. Tested the last version and working fine.

I looked last week (and again just now a little deeper) and didn't see anything: e.g. Component: Disability Access APIs Product: Core - 1002 bugzillas and that's just the open ones

I think this pref is a red herring (reading some troubleshooting issues that also can't be reproduced they talk about being maximized, zoomed, and other steps - even e10s, yay!). But TBH, if enabling the cache is not a disk issue, and it works, then just do it. We'll be on ESR115 in a few months :)

tested on win 10 with windows Narrator. used pierov's build and it was able to read page contents to me

mentioned in merge request tpo/web/blog!199 (merged)

mentioned in merge request !687 (merged)

Opened !687 (merged) for the moment.

mentioned in issue #41761 (closed)

I've just tested a 13.0ax Windows testbuild with Windows narrator and everything works for me.

for the record ... accessibility.cache.enabled was removed in FF115 1821955 part 6

We don't set it in our profiles in the 115 branch already.

So, I think we can close.

closed

removed Backlog label