1835654 - [Intermittent] [Nightly] The Top Sites tiles are misaligned after restarting the browser while 2 Firefox windows are open in the same time

Status: NEW

(Firefox :: Top Sites, defect)

Description

[Carmen Fat [:cfat] - Ecosystem QA]

[Affected versions]:

• Firefox Nightly 115.0a1 (Build ID: 20230529093707)

[Affected Platforms]:

• Windows 10 x64
• macOS 12.6.1
• Linux Ubuntu 20.04 x64

[Prerequisites]:

• Have a VPN client connected to a US server (for users located outside the US).

[Steps to reproduce]:

1. Open the browser from the prerequisites.
2. Open a new tab and make sure you have Sponsored Top Sites.
3. Restart the browser using the shortcuts (Ctrl+Shift+J then Ctrl+Alt+R).
4. Dismiss the Default browser message.
5. Press the Ctrl+N shortcut to open a New Firefox Window.
6. Restart the browser using the shortcuts (Ctrl+Shift+J then Ctrl+Alt+R).
7. Observe the Top Sites.

[Expected result]:

• All the Top Sites have the same alignment.

[Actual result]:

• The Sponsored Top Sites are misaligned.

[Notes]:

• I also noticed that dismissing Sponsored Top Sites will lead to empty tiles being misaligned as well.
• I was not able to reproduce this issue on the Beta and Release channels.
• Here is a screen recording with the issue.