1640182 - [Windows 8.1] Missing left border on the first tab when Menu Bar is enabled

Status: NEW

(Firefox :: Tabbed Browser, defect)

Description

[Bogdan Maris [:bogdan_maris], Release Desktop QA]

Attachment: Image showing the issue

Affected versions

• Firefox 77.0b9
• Firefox 76.0
• latest Nightly 78.0a1

Affected platforms

• Windows 8.1 32bit

Unaffected platforms

• Windows 10 64bit
• Ubuntu 18.04 64bit
• MacOS 10.15.5 beta 3

Steps to reproduce

1. Start Firefox
2. Enable Menu Bar (right click in tab bar and enable Menu Bar)

Expected result

• No visual defects can be seen in the Tabbar

Actual result

• Left border of the first Tab is missing

Regression range

• First bad: 2017-09-26
• Last good: 2017-09-27
• Pushlog: https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=33b7b8e81b4befcba503c0e48cd5370aeb715085&tochange=7d15bc419c6cd7e9f3b4d41370c3b0e5990c8d1b
• Potential regressor: Not sure which one could be the regressor here, someone who is involved in this area maybe able to determine the culprit.

Additional notes

• Image with the issue is attached.