User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:93.0) Gecko/20100101 Firefox/93.0

Steps to reproduce:

Clicked "About Firefox"

Actual results:

The screen flashed as the window loaded in the upper-lft corner of the screen, and flashed again a split-second later as it loaded in the middle.

Expected results:

It should load once, not twice.

Same behavior in troubleshoot mode.

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

I'm going to move this to accessibility to give it more visibility. The fix will most likely be under Widget::Cocoa though.

We should triage this to where it'll be fixed.
We use the 'access' keyword along with the '[access-sX]' whiteboard tag to track accessibility-relevant bugs that originate in other components.
Triaging as [access-s2] due to possible injury for users with vestibular disabilities.

Is this a regression?

I see this for a very long time (over a lot of FF Stable Releases now.)

Hi Markus,

I did a manual bisect and found the regression range:

Good Build: 2021-08-03-22-01-19-mozilla-central/

Bad Build: 2021-08-04-09-39-31-mozilla-central/

I hope this helps you to find the culprit change.

Thanks :)

Thanks! I was still able to reproduce it in your good build, so I used mozregression to find a new regression range, and it led me to bug 1660392. And it turns out this bug is already tracked as a regression from that, in bug 1738056.

Thanks for your follow up and finding the report that is already tracking the regression.