1765624 - [Android] On bit.ly 404 page, the "Log In" & "Sign Up" links shift to the left when you scroll (i.e. when dynamic toolbar disappears)

Status: NEW

(Core :: Layout: Scrolling and Overflow, defect, P3)

Description

[Daniel Holbert [:dholbert]]

STR:

1. In Firefox for Android, visit any nonexistent bit.ly page, e.g. https://bit.ly/no-such-link
   (To be clear: "no-such-link" isn't a meaningful suffix; it's just a bogus string that I picked at random)

2. On the resulting bit.ly 404 page, scroll downwards to make your dynamic toolbar disappear.

ACTUAL RESULTS:
The "Log In" and "Sign Up" links at the top right of the screen jump to the left a little bit.

EXPECTED RESULTS: No such jump.

NOTE:
This happens regardless of whether the toolbar is at the top or the bottom.
This is not reproducible in Chrome. (I can scroll the toolbar away in Chrome, but these links don't jump sideways like they do in Firefox.)

Comment 1

[Daniel Holbert [:dholbert]]

Also worth noting: this only happens in when I hold my phone in Portrait mode. It doesn't happen if I rotate my phone to Landscape mode.

My environment: I'm using a Pixel 4a with latest Firefox Nightly (v101), with Android version 12.

Comment 2

[Daniel Holbert [:dholbert]]

Hmm, so it looks like the header element has position:fixed; width: 100%, and for some reason that element ends up 4px wider when the dynamic toolbar is visible, vs. when the dynamic toolbar is hidden.

(And that impacts the positioning of these links, since they're placed at the right side of this header.)