[tbb-bugs] #27503 [Applications/Tor Browser]: Disabling accessibility on Windows breaks screen readers

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#27503: Disabling accessibility on Windows breaks screen readers
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 Reporter:  gk                                   |          Owner:
                                                 |  pospeselr
     Type:  defect                               |         Status:
                                                 |  assigned
 Priority:  High                                 |      Milestone:
Component:  Applications/Tor Browser             |        Version:
 Severity:  Normal                               |     Resolution:
 Keywords:  tbb-8.0-issues, tbb-regression,      |  Actual Points:
  GeorgKoppen201903, tbb-8.5-must,               |
  TorBrowserTeam201904                           |
Parent ID:                                       |         Points:
 Reviewer:  boklm                                |        Sponsor:
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Comment (by gk):

 Replying to [comment:58 gk]:
 > Replying to [comment:57 pospeselr]:
 > > I've built and tested 64 bit as well and see the same behavior as
 described above in 64-bit Windows 10 with (ie able to read page contents
 via mouse-over using NVDA)
 > >
 > > Here's the current changeset used to build the above nightlies
 (literally just the current patch from the Mozilla bug)
 > >
 > > https://gitweb.torproject.org/user/richard/tor-
 browser.git/commit/?h=bug_27503_v2
 >
 > Okay, I looked at the history of where I left dealing with the bug
 figuring out why this seems to work better now.
 >
 > So, in ESR 60.5.0 all the patches done by Jacek in
 https://bugzilla.mozilla.org/show_bug.cgi?id=1430149 landed. The still
 relevant comments then start with comment:36. I _think_ I built the bundle
 there with the patch in your `bug_27503_v2` applied. While I did not
 expect the bundle closer it asserts at the same place as Tom's
 https://treeherder.mozilla.org/#/jobs?repo=try&revision=c5ef984f2726adce22144c7a0d843ae761b94c6e
 (see Jacek's comment in
 https://bugzilla.mozilla.org/show_bug.cgi?id=1520177#c15 and the attached
 debuglog.txt to this bug). I think my
 https://bugzilla.mozilla.org/show_bug.cgi?id=1520177#c19 is referring to
 that.
 >
 > All those builds are *debug* builds, however, while yours are none it
 seems. Thus, one thing we could test is whether you see the same problem
 compiling with `--enable-debug`.

 Yes, that's been it: we are hitting the assert on the debug builds which
 result in a broken experience. The non-debug builds (i.e. those we ship)
 are less affected: there is accessibility support even though it's not
 fully on par with that offered by vanilla Firefox). I'll take the patch
 from pospeselr's `bug_27503_v2` for the upcoming alpha to give it wider
 testing. That's commit f5f845f5fe14b5085f919ba46ec092b14c7fcb11 on `tor-
 browser-60.6.1esr-8.5-1` and will hopefully be available in 8.5a11.

 Leaving this ticket open to investigate and fix the remaining issues.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/27503#comment:59>
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