1918843 - Custom Tab Toolbar sometimes flickers to a brief rendering with tracking-protection-shield present and pushing lock/title/URL rightwards

Status: NEW

(Firefox for Android :: Toolbar, defect)

Description

[Daniel Holbert [:dholbert]]

Attachment: screenshot

Steps to reproduce

1. Tap a link to this article in some external app (e.g. gmail, or in my case X/Twitter):
   https://www.thebaltimorebanner.com/economy/growth-development/baltimore-county-sparrows-point-glove-factory-7EK3V6RJWRHRVOZZRD6HCR5CLY/?s=09
2. As the article loads in a custom tab, watch the left side of the toolbar very carefully.

Expected behavior

No strange flickers.

Actual behavior

After the lock, page title, and URL are displayed, there's sometimes an extremely brief flicker where that content all jumps rightwards, dodging a Tracking Protection shield that appears out of nowhere. (You can't really tell what's happening because it's so fast -- it just looks like the content changes entirely for a fraction of a second and then changes back.)

Device information

• Firefox version: Nightly 132.0a1 2024-09-12
• Android device model: Pixel 8
• Android OS version: 14

Any additional information?

See attached screenshot. I'll post a screencast too where you can see the flicker if you watch very closely (ideally in slow-motion).

Comment 1

[Daniel Holbert [:dholbert]]

Attachment: screencast of bug (flicker is at t=1s)

Comment 2

[Daniel Holbert [:dholbert]]

Attachment: slow-motion presentation of screenast (10% speed)

Here's a simple html document that plays back the screencast at 10% speed, which makes the issue (at t=1s) easier to see.

Comment 3

[BugBot [:suhaib / :marco/ :calixte]]

The severity field is not set for this bug.
:007, could you have a look please?

For more information, please visit BugBot documentation.

Comment 4

[Noah Bond [:007]]

moving this to Toolbar