2009241 - Firefox logo and private-browsing-mask-button change position on new-tab page, when you tab the Private Browsing mask button

Status: ASSIGNED

(Firefox for Android :: Homepage, defect)

Description

[Daniel Holbert [:dholbert]]

Steps to reproduce

1. Open a new tab in Firefox Nightly
2. Tap the mask in the upper right corner, and pay close attention to the Firefox Nightly logo/wordmark in the upper left corner

Expected behavior

Firefox Nightly logo/wordmark should not move.

Actual behavior

Firefox Nightly logo/wordmark moves upwards as I enter Private Browsing.

Device information

• Firefox version: 148.0a1
• Android device model: Pixel 10 Pro XL
• Android OS version: 16

Any additional information?

This is a regression; current beta 147 gives expected results.

Comment 1

[Daniel Holbert [:dholbert]]

Attachment: screencast of bug

Comment 2

[Daniel Holbert [:dholbert]]

Actually, more concerning than the Firefox-logo-moving -- the "mask" button itself (at the top right) shifts upwards too (as it changes state).

That's a bit concerning/annoying because it's never great for content to move out from under your finger/mouse when you touch it.

Comment 3

[Daniel Holbert [:dholbert]]

Newest known good nightly: 2025-12-16 https://hg-edge.mozilla.org/mozilla-central/rev/f4fbbc7362a7eab29fc453378bd4aa8d61eb394e
Oldest known bad nightly: 2025-12-17 https://hg-edge.mozilla.org/mozilla-central/rev/66a2bb093b81686973b18f82f747f20ca020c487

Pushlog: https://hg-edge.mozilla.org/mozilla-central/pushloghtml?fromchange=f4fbbc7362a7eab29fc453378bd4aa8d61eb394e&tochange=66a2bb093b81686973b18f82f747f20ca020c487

Not sure which of the Android changes in there might be involved; maybe bug 2004410 somehow? (shot in the dark -- maybe the "privacy notice banner" goes at the top of the homepage, and when it's not shown, the new codepath still sets aside some blank space for it somehow?)

Whatever caused this, it does look like the proximal behavior-change was that we added a bit more spacing above the "top row" (Firefox Logo + private-browsing-mask-button) on the regular new-tab homepage, and that spacing is not present on the private-browsing new-tab homepage.

Comment 4

[Daniel Holbert [:dholbert]]

(tentatively flagging as regression from bug 2004410 per previous comment. @joberhauser maybe you could take a look, or maybe you see another likely regressor in the pushlog?)

Comment 5

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

Set release status flags based on info from the regressing bug 2004410

Comment 6

[John Oberhauser]

Looks like this was a regression from me. I'll fix it.

Comment 7

[John Oberhauser]

Attachment: Bug 2009241 - Fixing an issue where the homepage header moves when switching between normal and private mode