1399455 - First window paint draws the border on Windows 7

Status: NEW

(Core :: Graphics, defect, P3)

Description

[Adrian Florinescu [:aflorinescu] [PTO till 06/12, redirect to [e-mail]/[e-mail]]]

[Environment:]
Windows 7 x64 - Version 57.0a1 20170912220343

[Steps:]
1. Open a screen recorder.
2. Open Firefox.
3. Analyze the Firefox start-up.

[Actual Result:]
See https://www.youtube.com/watch?v=Xur9fq47p7s (Firefox window border is first painted)

[Expected Result:]
The Firefox window should be painted directly without any transition, though I'm not sure what's causing the border to be drawn first for Win7. 

[Note:]
This scenario is particular to Win7. I haven't seen this in Linux/Win10, Win8.1 cases.

Comment 1

[Adrian Florinescu [:aflorinescu] [PTO till 06/12, redirect to [e-mail]/[e-mail]]]

Windows 7 x64
FF 55.03 20170824053622  - not reproducible
FF 56.0b11 20170911193316 - reproducible
therefore concluding it is not a regression introduced by bug 1362103;

updating flags accordingly.

Comment 2

[Daniel Bodea [:danibodea]]

After a detailed investigation I managed to come up with these results:
Tested mozilla-central build: 2017-03-15 (verdict: g)
Tested mozilla-central build: 2017-03-16 (verdict: b)

Tests were done with and without mozregression, on Windows 7 x64.