When you have a video with captions, the tab order looks like this. First tab focuses the video frame. Second tab focuses the cc button. Third tab focuses the full-screen button.

(Note: you won't see a focus indicator. Bug report upcoming.)

When you have a video without captions, the tab order looks like this. First tab focuses the video frame. Second tab goes to the hidden cc button. Third tab goes to the full-screen button.

When the video doesn't have captions, the cc button is hidden visually but the tab stop is not removed. We should remove it.

Steps to reproduce.

1. Load the video test case from https://bug1665235.bmoattachments.org/attachment.cgi?id=9175929
2. Tab to focus the video
3. Tab a second time and notice focus goes into a black hole.
4. Tab a third time and focus goes to the full-screen button.

Results: Because the video has no captions, we hide the cc button visually but we do not hide it from focus.

Expected results: After tabbing to focus a video without captions, the next tab key should land on the full-screen button.

Tested on today's Nightly on Windows 10

(In reply to Asa Dotzler [:asa] from comment #0)

Steps to reproduce.

1. Load the video test case from https://bug1665235.bmoattachments.org/attachment.cgi?id=9175929
2. Tab to focus the video
3. Tab a second time and notice focus goes into a black hole.

For me, focus goes to the PiP button. There might not be a focus indicator on that, it doesn't support keyboard activation (bug 1665251) and neither the CC button nor the new PiP button have a11y labels, so it's difficult to know what has focus... but NVDA developer info reports that the focus has an id of "pictureInPictureToggleExperiment". You can see this info by pressing NVDA+f1 after you move focus and looking at the "IAccessible2 attributes:" line at the bottom. Can you confirm what you see here?

Yes. I get what you get. It is indeed the PiP button but the NVDA developer info reports pictureinpicturetoggle.

In that case, I think we can close this as a duplicate of bug 1665251. I don't understand why having captions (or not) impacts whether PiP is available here. Regardless, the button we're seeing here is the PiP button, not something related to captions.