1867239 - [Macbook Air M2] Full-screen Firefox gets resized wrongly when moving from a full monitor to one with the notch

Status: RESOLVED FIXED

(Core :: Widget: Cocoa, defect, P3)

Description

[Nicolò Ribaudo]

I have a MacBook Air M2, that has the notch at the top of the display. In my macOS settings, I have "Automatically hide and show the menu bar" option set to "In Full Screen Only".

When I open Firefox in fullscreen, the menu bar is at the same level as the notch (with the notch covering part of the bar), as it happens for all other apps. Note that the menu bar is only visible when I hover it, but there is still some "black space" in my display where it will appear (again, this is normal macOS behavior).

When I open Firefox on a second monitor without the notch, Firefox takes all the available space to the top. When I move my mouse to the top of the screen, the menu bar slides down from the top of the display.

When I open Firefox on the second monitor and then I move it to the built-in screen, Firefox resizes to be narrower than the available display width. Additionally, when I move the mouse to the top of the screen the menu bar slides down below the notch rather than appearing at the same level as the notch.

Exiting and re-entering full-screen, or toggling the "Automatically hide and show the menu bar" macOS option, makes Firefox re-render correctly.

I tried recording my screen but unfortunately from there it looks like everything is ok, so I recorded it with an external camera. Hopefully it shows the problem :)
(EDIT: The attachment makes bugzilla go 502, I'll attach it later)

Comment 1

[Nicolò Ribaudo]

Attachment: Screen recording

Comment 2

[Dan Mosedale (:dmosedale, :dmose)]

Thanks for the bug report! It would help understand what the right behavior would actually be if you could write up the current behavior and then contrast it with the expected behavior. Would you be willing to take a shot at it?

Comment 3

[Fred Chasen [:fchasen]]

Attachment: Full width of the screen

Comment 4

[Fred Chasen [:fchasen]]

Attachment: Fullscreen narrower than the width of the screen

Comment 5

[Fred Chasen [:fchasen]]

Attachment: The moment of the video when the fullscreen width narrows

Comment 6

[Fred Chasen [:fchasen]]

Thanks again for the report, was difficult to tell the issue from the video but I was able to reproduce this using your steps (on an m1 pro laptop + monitor) and as you mentioned sadly screen recordings don't pickup the issue.

I've attached two screenshot from the video with arrows to better show the change in width and a trimmed version of the video showing the width narrowing which hopefully make it clearer how the total fullscreen width is shrinking.

Comment 7

[Nicolò Ribaudo]

I just noticed that when Firefox is being rendered "small" and I lock my screen, even the lockscreen gets rendered small. I'm attaching two images showing the difference.

Comment 8

[Nicolò Ribaudo]

Attachment: Locked screen with "smaller firefox window" active before locking

Comment 9

[Nicolò Ribaudo]

Attachment: Locked screen with any other app (or "normal-sized firefox") active before locking

Comment 10

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

The severity field is not set for this bug.
:mossop, could you have a look please?

For more information, please visit BugBot documentation.

Comment 11

[Nicolò Ribaudo]

Hey, has this bug been fixed?

I decided to try fixing it by myself, so I build Firefox from source but I cannot reproduce it on the current mozilla-central tip. I think it might have been fixed by https://phabricator.services.mozilla.com/D197903?

This looks like something difficult to write tests for, so I'm just marking this as fixed.