1516490 - firefox unloads looping video when out of view causing some pages to re-arrange

Status: RESOLVED FIXED

(Core :: Layout, defect, P3)

Description

[sguergachi]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:65.0) Gecko/20100101 Firefox/65.0

Steps to reproduce:

1. Go to this webpage: https://brianlovin.com/design-details/square-order-ios
2. Scroll slowly (to allow videos to load)
3. Stop at heading: "Add an item" and wait 6 secs.


Actual results:

Notice the page scroll position changes. This is because the videos that are looping above seemed to have been unloaded and their size on the page made smaller.

Quickly scrolling up to top of page will reveal this.


Expected results:

The expected result (and what Chrome does currently) is to ensure the dimensions of the video are kept as is, even when unloaded.

Comment 1

[Gyula Palko[:gpalko]]

I can reproduce this on the latest builds from all channels, I'm adding the component in order to involve the development team. 
Thanks for reporting!

Comment 2

[Emilio Cobos Álvarez (:emilio)]

(In reply to sguergachi from comment #0)
> The expected result (and what Chrome does currently) is to ensure the
> dimensions of the video are kept as is, even when unloaded.

Is it really doing that?

I suspect the explanation between Chrome and Firefox may be scroll anchoring, but can't check right now.

It may be worth to check what Edge does too to see if there's something more subtle.

Comment 3

[Xidorn Quan [:xidorn] UTC+11]

I would have the same guess that it's because of Chrome's scroll anchoring. It might be worth checking whether bug 1305957 would fix this.

Comment 4

[Ryan Hunt [:rhunt] (on leave until early May)]

I can confirm that the current scroll anchoring patches make that page much easier to read.

Comment 5

[Ryan Hunt [:rhunt] (on leave until early May)]

Would you be able to test this in the latest nightly and see if scroll anchoring has resolved this for you?

It seems much better now.

Comment 6

[sguergachi]

Seems to be fixed in latest nightly!

Comment 7

[Ryan Hunt [:rhunt] (on leave until early May)]

Awesome, glad to hear it.