1406435 - [macOS] Top border of Default and Dark Theme flashes white when the window moves out of the Dock

Status: NEW

(Core :: Widget: Cocoa, defect, P2)

Description

[Mehmet]

Attachment: white_flicker_top_border.mov

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3234.0 Safari/537.36

Steps to reproduce:

macOS 10.12.6
58.0a1 (2017-10-06) (64-Bit)

1.) Open a new window and select the Default or Dark Theme
2.) Minimize this window into the Dock
3.) Move it out of the Dock


Actual results:

The top border of the window flashes white.


Expected results:

It should not flash white. This happens with the Default and Dark Theme. Maybe also with the Light Theme, but there it is probably not so much noticeable.

A screencast is attached.

Thanks.

Comment 1

[Johann Hofmann [:johannh]]

I can reproduce this with 57/58 but not on 56.

I'm just assuming this is a Widget issue, but I don't really know. In any case, I don't think this is a high-priority issue.

Would you like to try and get a regression window using mozregression?

Thanks!

Comment 2

[Mehmet]

(In reply to Johann Hofmann [:johannh] from comment #1)
> I can reproduce this with 57/58 but not on 56.
> 
> I'm just assuming this is a Widget issue, but I don't really know. In any
> case, I don't think this is a high-priority issue.
> 
> Would you like to try and get a regression window using mozregression?
> 
> Thanks!

Of course, I'll try to find the regression range later.

Comment 3

[Mehmet]

(In reply to Johann Hofmann [:johannh] from comment #1)
> I can reproduce this with 57/58 but not on 56.
> 
> I'm just assuming this is a Widget issue, but I don't really know. In any
> case, I don't think this is a high-priority issue.
> 
> Would you like to try and get a regression window using mozregression?
> 
> Thanks!

Okay, I did a bisect and here is the regression range:

Good Build: 57.0a1 (2017-08-11) (64-bit)

Bad Build: 57.0a1 (2017-08-12) (64-bit)

I hope this helps.

Comment 4

[Mehmet]

May be: https://hg.mozilla.org/mozilla-central/rev/8fa9361b1968 ?

Comment 5

[Johann Hofmann [:johannh]]

Yeah, maybe. Markus, what do you think? Again, I'd say it's low-prio but it would be good to know about the regressor.

Comment 6

[Markus Stange [:mstange]]

Bug 1372602 seems like a plausible regressor. I haven't checked to confirm.

The problem here could be something similar to the one in bug 1391606, which I haven't had a chance to debug yet.