[Affected versions]: - latest Nightly 50.0a1 [Affected platforms]: - Mac OS X 10.12 Sierra Beta (16A239j) [Steps to reproduce]: 1. Start Firefox 2. Enter Customize 3. Exit Customize [Expected result]: - The transition is smooth [Actual result]: - There is a visible lag when entering/exiting customize mode [Regression range]: - Not sure if this is a regression, will investigate further ASAP. [Additional notes]: - Screnncast showing the issue attached - I was unable to reproduce on other version of Firefox (beta, release, DevEdition).

(In reply to Bogdan Maris, QA [:bogdan_maris] from comment #0) > [Regression range]: > - Not sure if this is a regression, will investigate further ASAP. Yes please!

I tried to find a regression range but mozregression was not able to open any version of Nightly older than one month. Is there a way I can find a regression in this circumstances?

(In reply to Cipri [:ciprian_georgiu] from comment #2) > I tried to find a regression range but mozregression was not able to open > any version of Nightly older than one month. Is there a way I can find a > regression in this circumstances? You may need to specify --bits 32 to get a 32-bit build. I don't know when 64-bit builds started but they won't go that far back.

(In reply to Jared Wein [:jaws] (please needinfo? me) from comment #3) > (In reply to Cipri [:ciprian_georgiu] from comment #2) > > I tried to find a regression range but mozregression was not able to open > > any version of Nightly older than one month. Is there a way I can find a > > regression in this circumstances? > > You may need to specify --bits 32 to get a 32-bit build. I don't know when > 64-bit builds started but they won't go that far back. This is on OSX, where we ship doubled-up builds, so that isn't the problem. I think our builds didn't use to start on 10.12 (the new beta version of OSX) until recently. Maybe :mstange can help.

(though tbh it's not clear this is materially different from bug 1287156 in which case investigating this separately may not be a good use of our time)

Right, I don't think there's anything we should do here until bug 1287156 is resolved.

This is fixed in the latest Sierra Beta (which fixed bug 1287156).