1697107 - Other buttons are displayed under the "Open a new tab" button and the "x" button from the new opened tab

Status: RESOLVED WORKSFORME

(Firefox :: Tabbed Browser, defect, P3)

Description

[Hani Yacoub, Desktop QA]

Attachment: Screenshot 2021-03-09 at 10.44.31.png

Preconditions

In about:config set:
browser.proton.enabled = true
browser.proton.tabs.enabled = true

Affected versions

Firefox 88.0a1

Affected platforms

MacOS 10.15
Windows 10 x64
Ubuntu 20.04 x64
Windows 7 x64

Steps to reproduce

1. Open Firefox.
2. Open many tabs till the last opened tab is displayed at the far right of the window.
3. Open a new tab and observe "Open a new tab" button and the "x" button from the new opened tab.

Expected result

No flicker should be displayed on the "Open a new tab" button and the "x" button from the new opened tab.

Actual Result

• ”List all tabs” button is displayed under the ”+” button (like a flicker) after clicking on “+”
• While clicking on + button, x button for the new open tab is displayed + before switching to x (flicker)

Note

I did a slow motion video to capture this:
https://streamable.com/u8nmsh

Comment 1

[Hani Yacoub, Desktop QA]

This issue isn't reproducible anymore on Firefox Nightly 89.0a1 (2021-03-29) on Window 10 x64, macOS 10.15, Windows 7 x64 and on ubuntu 20.04 x64.