STR (with NVDA):

1. Open any document; e.g. data:text/html,foo
2. Open the page context menu and select Inspect Accessibility Properties.
3. Focus the Accessibility Tree.
4. Use the arrow keys to select a node.
5. Right click on the node to open the context menu.
   Expected: NVDA should say "menu".
   Actual: NVDA says "text frame" then "menu".
6. Press escape to dismiss the menu.
   Expected: NVDA should speak the item selected in step 4.
   Actual: NVDA speaks "text frame" instead of the item.

I think the tbody gets DOM focus when you click in the tree view. It does have role="presentation", but we ignore that for nodes which can get DOM focus. Assuming I'm correct (I haven't looked at the code), there are two possible solutions:

1. The tbody shouldn't be focusable. This has the added benefit of pruning the tbody from the a11y tree. While the ideal solution, I'm guessing it had to be made focusable for some implementation reason.
2. Set aria-activedescendant on the tbody to also reference the active tree item. This way, when the tbody does get focus, a11y clients won't really notice it.

This used to work fine, so I'm marking this as a regression.

MozReview-Commit-ID: 2kzvA2Eb1eF

Backout for browser_inspector_extension_sidebar.js, dt failure, on a CLOSED TREE

Push with failure: https://treeherder.mozilla.org/#/jobs?repo=autoland&resultStatus=testfailed%2Cbusted%2Cexception%2Csuperseded%2Crunnable&classifiedState=unclassified&revision=611bd5949e8303b918da760d8e01caae8d30ec80&selectedJob=222826759

Backout log: https://hg.mozilla.org/integration/autoland/rev/1c7ed5d9e1fe429f8a753b40156744b73ef12cda

Failure log: https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=222829598&repo=autoland&lineNumber=12535

Backed out changeset 50cc5c5bd5ef (Bug 1520107) for mochitest failures at test_accessible_row_context_menu.html

Backout: https://hg.mozilla.org/integration/autoland/rev/1aee4f577b05824f71ca36db2ab640e76d90cc60

Push that started the failures: https://treeherder.mozilla.org/#/jobs?repo=autoland&resultStatus=pending%2Crunning%2Csuccess%2Ctestfailed%2Cbusted%2Cexception&revision=50cc5c5bd5efdb15adda6b1490ecf907f5fe100b&selectedJob=222885265

Failure log: https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=222885265&repo=autoland&lineNumber=2349

https://hg.mozilla.org/mozilla-central/rev/6aa3c460ff66

Too late for 65.