1404713 - Can't enter fullscreen on youtube after moving a tab to another window.

Status: RESOLVED WORKSFORME

(Firefox :: Tabbed Browser, defect, P2)

Description

[Johan C]

Attachment: Browser Console output

STR:
1. Open two window.
2. Open a video on youtube in one window.
3. Move the "youtube"-tab to the other window.
4. Double-click or click the fullscreen button on the video.

Expected: Video goes fullscreen.

Actual: Nothing.

Note:
If you blur and return focus to the window with the broken "Youtube"-tab fullscreen magically fixes itself.

I've attached the output from the Browser Console, the console was cleared immediately before moving the tab between the two windows.

Comment 1

[Johan C]

This is a regression, currently working on narrowing it down with mozregression, details incoming.

Comment 2

[Johan C]

From mozregression-gui's "Bisection informations":

app_name: firefox
build_date: 2017-05-23 18:51:36.638000
build_file: C:\Users\[redacted]\.mozilla\mozregression\persist\aa48bb3f4944--autoland--firefox-55.0a1.en-US.win64.zip
build_type: inbound
build_url: https://queue.taskcluster.net/v1/task/N0XM82LgT8ysRFUytWqWeQ/runs/0/artifacts/public%2Fbuild%2Ffirefox-55.0a1.en-US.win64.zip
changeset: aa48bb3f494410de514041e8c06ca15c38680181
pushlog_url: https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=d11aec13b38e0837c07d0906c1ab506e162b2a2f&tochange=aa48bb3f494410de514041e8c06ca15c38680181
repo_name: autoland
repo_url: https://hg.mozilla.org/integration/autoland
task_id: N0XM82LgT8ysRFUytWqWeQ

I'm not entirely sure how to interpret this myself, but to me it looks like bug 1362866 regressed this?

Mike, it looks like you worked on the bug mentioned, do you think it could be the cause of this regression? (sorry if this is misuse of ni? by the way.)

Comment 3

[:Gijs (he/him)]

Confirmed that this is bug 1362866...

https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=6d4744a6c81c498cc81cad11b4ead64660a3d269&tochange=aa48bb3f494410de514041e8c06ca15c38680181

[Tracking Requested - why for this release]:
While the symptoms here aren't terrible, and we've shipped this in 55 and 56 now, I am... concerned... that the media fullscreen code doesn't think the tab has focus after moving it to a new window. It should know that it does, and the internal state being bust might have other ramifications. :-(

Comment 4

[:Gijs (he/him)]

(FWIW, the relevant bit of the console output is "Request for fullscreen was denied because requesting element is not in the currently focused tab." )

Comment 5

[:Gijs (he/him)]

We must be failing this check:

https://dxr.mozilla.org/mozilla-central/rev/11fe0a2895aab26c57bcfe61b3041d7837e954cd/dom/base/nsDocument.cpp#11927-11930

  if (!nsContentUtils::IsChromeDoc(this) && !IsInActiveTab(this)) {
    DispatchFullscreenError("FullscreenDeniedNotFocusedTab");
    return false;
  }

IsInActiveTab looks like this:

https://dxr.mozilla.org/mozilla-central/rev/11fe0a2895aab26c57bcfe61b3041d7837e954cd/dom/base/nsDocument.cpp#11786-11823

and checks both the docshell's isActive flag and whether the focus manager thinks the docshell's root window is the active window.

Comment 6

[Julien Cristau [:jcristau]]

OK, let's track this for now.

Comment 7

[Liz Henry (:lizzard) (relman/hg->git project)]

Too late for uplift to 57. We could still take a patch for 58 though.

Comment 8

[Mike Conley (:mconley) (:⚙️)]

Apologies - declaring needinfo bankruptcy on needinfo's greater than 2 years old.

Comment 9

[Augusto Pace]

Hi,

I'm not able to reproduce this issue on Windows 10 for Firefox version Nightly 74.0a1 (2020-01-23) (64-bit) - Beta 73.0b8 (64-bit) - Release 72.0.2 (64-bit). Marking those flags as unaffected.

Comment 10

[:Gijs (he/him)]

Reporter, are you still seeing this? It's been a while, so if this is fixed it'd be useful to close the bug; if not, it'd be useful to have more details as to how to reproduce, so we can clarify which versions remain affected...

Comment 11

[Johan C]

(In reply to :Gijs (he/him) from comment #10)

Reporter, are you still seeing this? It's been a while, so if this is fixed it'd be useful to close the bug; if not, it'd be useful to have more details as to how to reproduce, so we can clarify which versions remain affected...

Sorry for the delayed reply.

I cannot reproduce this issue with Firefox 72.0.2 (64-bit).

Comment 12

[Julien Cristau [:jcristau]]

Thanks for following up Johan!