1680648 - marquee animation is broken if Partial Prerender is enabled

Status: RESOLVED DUPLICATE of bug 1679649

(Core :: CSS Transitions and Animations, defect)

Description

[Daniel Holbert [:dholbert]]

STR:

1. Visit https://www.jackery.com/pages/give-the-gift-of-power
2. Scroll down to the marquee, below the array of 5 face-down playing cards

EXPECTED RESULTS:
The marquee should be moving.

ACTUAL RESULTS:
The marquee does not move. And if you wait a little while, it starts getting slowly "eaten" from the left edge while not moving. (i.e. the parts that should be animating out-of-view just disappear instead of moving)

This is a "marquee" with a custom implementation using a CSS animation, rather than an html <marquee> tag.

If I set layout.animation.prerender.partial to false, then the bug goes away, so I'm pretty sure this is a bug in the partial prerender implementation. (Maybe even related to bug 1679649, if we're lucky?)

Comment 1

[Daniel Holbert [:dholbert]]

Attachment: testcase 1 (somewhat reduced)

Here's a partially reduced testcase.

Comment 2

[Daniel Holbert [:dholbert]]

I just confirmed that the reduced testcase is broken for me in Nightly, regardless of whether WebRender is enabled. So, this is not WebRender-dependent in any way.

Comment 3

[Hiroyuki Ikezoe (:hiro)]

Yeah, the reduced case is definitely another variant of bug 1679649, there is an overflow: hidden element offseted from the reference transform frame by top: 350px.

Comment 4

[Daniel Holbert [:dholbert]]

That's good news! Thanks for checking.