1850973 - Delay when focussing Firefox on MacOS

Status: RESOLVED DUPLICATE of bug 1808223

(Core :: Widget: Cocoa, defect)

Description

[isra017]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:109.0) Gecko/20100101 Firefox/116.0

Steps to reproduce:

1. Use Firefox for many days.
2. Switch to another application
3. Switch back to Firework (Cmd + Tab)

Actual results:

Firefox seems become the active application, the the window won't focus before at least 1 second. If the window is already visible, it still won't be responsive to mouse or keyboard event before at least 1 second.

Once in focus, the application work as usual. Memory and CPU look as usual as well. There are more than enough memory on the system, swapping is unlikely.

Quitting Firefox and opening it again fix the issue.

Similar users having this issue:

• https://old.reddit.com/r/firefox/comments/xwlpxy/on_macos_commandtab_switching_to_firefox_lags/
• https://old.reddit.com/r/firefox/comments/qr15hb/switching_to_firefox_with_commandtab_on_mac_has_a/

It has been going on for more than a year.

I am using the latest Firefox (116.0.3 ) on the latest MacOS (13.1) on a Macbook Pro M1 14".

Expected results:

Focusing Firefox should make it responsive as soon as possible.

Comment 1

[isra017]

I'm not sure what kind of data can be useful to collect when the issue happen again. Feel free to ask for more detail with tools or command to use if needed.

Comment 2

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

The Bugbug bot thinks this bug should belong to the 'Core::Widget: Cocoa' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.