1830585 - Opening a new window when in fullscreen causes the tab in the new window to appear shifted to the right on macOS

Status: RESOLVED DUPLICATE of bug 1829403

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

Description

[caskets-06-mystery]

Attachment: bug.png

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:109.0) Gecko/20100101 Firefox/113.0

Steps to reproduce:

(Using Firefox Developer Edition 113.0b9, a new profile with no addons or changed settings, and macOS Ventura 13.2.1)

1. Open a new Firefox window
2. Click the green button to enter fullscreen
3. Press Cmd + N to create a new window

Actual results:

The tabs in the tab bar at the top of the window appear shifted to the right, leaving some blank space in the top left (see bug.png). It looks like it's leaving space for the red, yellow, and green buttons that normally appear at the top left of windows on macOS, but as this is fullscreen it should not appear.

This can be worked around by exiting fullscreen and reentering fullscreen - the tabs appear as expected after doing that.

As a bonus, when exiting fullscreen there is a strange blank space at the top of the window.

Expected results:

The tabs are flush against the top left of the window.

Comment 1

[Gregory Pappas [:gregp]]

This looks like it could be a regression. Please consider using mozregression to find the specific code change which introduced the issue.

Comment 2

[caskets-06-mystery]

I've run mozregression and it seems to be related to

Bug 1823284 - Use SizeModeChanged notification to handle fullscreen change; r=geckoview-reviewers,rkraesig,stransky,bradwerth,smaug,m_kato

Depends on D175213

Differential Revision: https://phabricator.services.mozilla.com/D175215

Comment 3

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

:edgar, since you are the author of the regressor, bug 1823284, could you take a look? Also, could you set the severity field?

For more information, please visit BugBot documentation.

Comment 4

[Brad Werth [:bradwerth]]

I'll take on this one; it's similar to other weird macOS fullscreen behavior that is tied to Bug 1631735.

Comment 5

[Edgar Chen [:edgar]]

I could not reproduce this anymore after Bug 1829403 (Nightly 2023-05-03 build).

Comment 6

[Brad Werth [:bradwerth]]

Now that the proposed fix in Bug 1829403 has landed, would you please try to replicate the issue with an updated Nightly build?

Comment 7

[caskets-06-mystery]

This bug no longer appears in the latest Nightly for me either (20230503140026). Thank you for the fix!

Comment 9

[Edgar Chen [:edgar]]

This isn't really a regression of Bug 1823284, bug 1823284 just changes some behavior and makes the underlying issue noticeable. The underlying issue was fixed in Bug 1829403.