1575130 - [10.15] Firefox won't display full screen video on external display on macOS 10.15

Status: RESOLVED DUPLICATE of bug 1631735

(Core :: Widget: Cocoa, defect, P2)

Description

[Liothen]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:70.0) Gecko/20100101 Firefox/70.0

Steps to reproduce:

• Macos 10.15 beta 6 with an external display or external display attached via e-gpu
• Load any youtube video on firefox onto an external display and hit full screen.

---

• chrome and safari work as expected and firefox works fine on primary display
• affects stable and nightly currently

Actual results:

App disappears just showing what ever window was below it or desktop if you had no other apps on the external display. You can click the background/app and it will send firefox to primary display.

Expected results:

Video should go full screen on display and play

Comment 1

[Gyula Palko[:gpalko]]

Hi,
I can't reproduce this on the latest Nightly 70 and Release 68 builds, using an iMac(macOS 10.15 beta 6) with an external display attached. Could you please open the Browser Console(Cmd+Shift+J) and check, if there's any error logged?

In the meantime, I'm linking this to the macOS 10.15 tracking bug, maybe somebody can reproduce it.
Thanks!

Comment 2

[Joe McCabe]

I can't reproduce this. WorksForMe.

Comment 3

[Joe McCabe]

Should have noted:
Firefox 60.0b16
macOS 10.15b6 (19A536g)
MacBook Pro (15-inch, 2017)

Comment 4

[Liothen]

I am still having this issue with the latest Firefox nightly. I have even tried starting it in safe-mode with the same result occurring.
when i check the console with safe-mode on there are no errors when this occurs, nor is there anything dumped to stderror on console.

if i hit escape while the video is playing in the background then it sends the browser to the laptops display.

my external display is 1440p 27" attached via an egpu (AMD RX 480)
Firefox 70.0a1 (2019-08-27) (64-bit)
macOS 10.15 Beta (19A536g)

Comment 5

[Haik Aftandilian [:haik]]

@Liothen, could you include the model of EGPU enclosure you're using? For debugging this, there are a few things you might try to get more information:

1. Errors might be being logged in Console. In the macOS Console application (/Applications/Utilities/Console), you can check for any errors or warnings that sound related. Try filtering on "firefox" or "plugin-container" and looking for anything that is logged when you enter full screen. In earlier macOS versions, Console had to be started before Firefox to get any log entries so I recommend starting Console first. Console logs a lot of information so I'd recommend clearing the log (using the Clear button in Console) right before trying to go fullscreen on Youtube.

2. You can retry the above after setting security.sandbox.logging.enabled=true in about:config and filtering on plugin-container. That logs sandbox-related events in Console. (Revert this back to false when done because the additional logging affects performance.)

3. Are you hitting any crashes? about:crashes would show any crashes being hit.

Comment 6

[Marcia Knous [:marcia]]

Reporter: Can you also test using the latest Mac seed? There have been several new betas since this bug was filed. Thank.

Comment 7

[Liothen]

Sorry for the delay on replying. I can find no errors in the console specific to console.
However i did experiment with setting the primary display. when i switch to the external display as primary then the issue only happens if i have firefox on my laptop screen and vice versa when i switch the laptop screen to primary.

Over the last few firefox nightly it has been affecting my context menus as well. if i right-click on a webpage the context menu will popup on the primary monitor if firefox is open on the secondary. if firefox is open on the primary then the context menus work as intended, this also affects the bookmark toolbar. I will attach a screenshot of this.

OSX 10.15 Beta (19A558d) - 71.0a1 (2019-09-18) (64-bit)

Comment 8

[Liothen]

Attachment: firefox-contextmenu.png

Context menu popping up on the primary display, but firefox is running on the secondary display

Comment 9

[BugBot [:suhaib / :marco/ :calixte]]

Bugbug thinks this bug should belong to this component, but please revert this change in case of error.

Comment 10

[BugBot [:suhaib / :marco/ :calixte]]

The priority flag is not set for this bug.
:spohl, could you have a look please?

For more information, please visit auto_nag documentation.

Comment 12

[Francesco Lodolo [:flod]]

As reported in bug 1575130, I can reproduce this with a display connected via AirPlay and current Nightly (74.0a1 (2020-01-18) (64 bit)).
OS is Catalina (10.15.2 (19C57)).

It's not limited to YouTube, it happens also with Netflix (and likely other video services).

Comment 13

[Francesco Lodolo [:flod]]

Interesting and weird workaround: switch Firefox to fullscreen (cmd+shift+F), then double click the video. For some reason, it goes fullscreen on the correct screen.

Comment 14

[David Christenson]

I previously experienced this bug. I discovered a few months ago that it happens when Firefox is assigned to a particular desktop. To fix/workaround it:

1. Right click on Firefox in the dock
2. Hover over Options
3. To the right it should have an Assign to menu listing your displays (if you have more than one space open in Mission Control)
4. Select None

Comment 15

[David Christenson]

Attachment: How to work around this bug

Comment 16

[Vlad Lucaci, Thunderbird QA (:vlucaci)]

Hello,

I have tried to reproduce this issue with 85.0(20210118153634) and 86.0a1(20210121094402) on an MacBook Pro A1278 laptop, attached to a Samsung S22B300 as well as a Samsung U28D590D monitor with an HDMI-DP adaptor and did not manage to reproduce it.

@Liothen , are you still able to reproduce this issue with the mentioned STR and affected device?

Comment 17

[Gian-Carlo Pascutto [:gcp]]

On an M1 Mac on Big Sur, using an USB4 -> HDMI Dongle, I can reproduce the following:

1. Move Firefox to secondary monitor (I'm using an old 1080p LED TV)
2. Open YouTube
3. Fullscreen the video

Sometimes (I think usually on the first attempt, it works the second time), Firefox will zap away and re-appear on the primary screen.

I'll try to get more precise STR.

Comment 18

[Catalin Sasca, Desktop Test Engineering [:csasca]]

Reproduced the initial issue on macOS 10.15.7 and macOS 11.2.2. This issue is reproducible if full-screen-api.macos-native-full-screen:false on latest Nightly 88.0a1 (2021-03-10).

Using full-screen-api.macos-native-full-screen:true with Nightly 88.0a1 (2021-03-10) the issue is no longer reproducible on macOS 10.15.7 and macOS 11.2.2. Closing this as a dupe of bug 1631735 which will resolve this issue as well after landing in Nightly.