1673454 - [Bug] Button in fixed position div disappears when updated via JavaScript

Status: NEW

(Core :: Web Painting, defect, P3)

Description

[Kevin Brosnan [Ex-Mozilla]]

From github: https://github.com/mozilla-mobile/fenix/issues/16173.

Steps to reproduce

1. Go to the following link (in Daylight, Beta, or Nightly): https://tonydang.blog/stackoverflow/1.html
2. Scroll to bottom
3. Click any of the "click" buttons

Expected behavior

Button in fixed position div at bottom should not disappear.

Actual behavior

Button in fixed position div at bottom disappears.

Device information

• Android device: Pixel 3a
• Fenix version: Daylight 82.1.1, Beta 82.0.0-beta.6, Nightly 201025 17:01

More info at this stackoverflow post: https://stackoverflow.com/questions/64530403/button-in-fixed-position-div-disappears-when-updated-via-javascript-only-occurs

I checked and this is not a problem in Chrome, Safari, Brave, nor Opera mobile browsers so assume it's Firefox specific. Works fine on Firefox desktop.

Change performed by the Move to Bugzilla add-on.

Comment 1

[Kevin Brosnan [Ex-Mozilla]]

I can reproduce this on Reference browser. GVE does not have a dynamic toolbar so does not reproduce.

Comment 2

[[ex-Mozilla] Agi Sferro | :agi]

Looks like this has something to do with fixed positioning.

Comment 3

[Emilio Cobos Álvarez [:emilio]]

I can repro. This only happens with the dynamic toolbar. So likely APZ related.

Hiro, do you have time to take a look?

Comment 4

[Hiroyuki Ikezoe (:hiro)]

Yeah, it's definitely related to dynamic toolbar, but I don't think it's APZ related. I think z-order of the position:fixed element is somewhat a problem. With disabling retained display list, I don't see the issue. Probably we need to take into account the expanded viewport (by the dynamic toolbar) for the position:fixed element somewhere in retained display stuff. Moving to Web Painting.

Comment 5

[f.pichlu]

I have this issue with fixed player in the bottom of page, you can reproduce bug when you play a music in the following path:
https://www.qwant.com/music/album/lonny-montem-what-kind-of-music-do-you-play-ep/overview

Comment 6

[f.pichlu]

I fixed it!
It caused by hiding address bar when you scrolling in the Firefox mobile app.
I resolve it by preventing hiding address bar with adding some styles to the parent element or a wrapper in the body (You can disable this option in the customize section of Firefox browser to test).

.wrapper {
position: fixed;
width: 100%;
height: 100%;
overflow-y: auto;
-webkit-overflow-scrolling: touch;
}

Comment 7

[Miko Mynttinen]

A testcase that reproduces with the desktop version of Firefox would be nice.