[css-overflow] Overflow propagation when the element propagated from is display: none

@lilles

https://drafts.csswg.org/css-overflow/#overflow-propagation says that some overflow properties should be propagated to the viewport from the html or body element:

However this happens regardless of the display value of the document element or the body. For example, the following examples show scrollbars:

data:text/html,<html style="display: none"><body style="overflow: scroll">
data:text/html,<html style="display: none; overflow: scroll">

This is the only case where Gecko needs to resolve a style in a display: none subtree for rendering (apart of getComputedStyle), and I find it somewhat silly.

Seems enough of an edge-case that could probably be changed. I wonder if there would be interest from other vendors in doing this change?

cc @lilles

Basically, my point is that this should be closer to the background style propagation, which only happens if the document element is actually displayed.

I think from an author standpoint this case doesn't matter, so personally I don't care. Happy to do whatever is expedient for implementers.

Fine for us from an implementation pov.

Chrome even propagates the background, which is not according to spec.

For backgrounds: https://bugs.chromium.org/p/chromium/issues/detail?id=947873

There is the same issue for https://drafts.csswg.org/css-writing-modes-3/#principal-flow

Chrome starts with the horizontal scrollbar to the right for direction:rtl regardless of display:none or not on body below.

<!DOCTYPE html>
<style>
  html { overflow: scroll; width: 5000px; height: 100px }
  body { direction: rtl; display: none }
</style>
<body></body>

Bug 1540220 - Remove some useless usage of LazyComputeBehavior::Allow…

The CSS Working Group just discussed Overflow propagation when the element propagated from is display: none, and agreed to the following:

RESOLVED: Do not propagate any style from display:none HTML or Body

The full IRC log of that discussion

<dael> Topic: Overflow propagation when the element propagated from is display: none
<dael> github: https://github.com//issues/3779
<dael> plinss: Who wants this one?
<dael> fantasai: Was emilio able to join?
<dael> emilio: Hey
<dael> emilio: This is mostly a little thing and only place where gecko needs to deep dive into the subtree to render
<dael> emilio: I remember rune at some point complained about it. I was wondering if people had willingness to change. I don't deeply care but I think it's a bitsaner
<dael> AmeliaBR: You're asking if the HTML or Body element isn't displayed we don't worry about prop. styles up?
<dael> emilio: Yes
<dael> plinss: Just get a blank page?
<bkardell_> seems fine?
<dael> smfr: display:none is common to do?
<dael> emilio: I dont think it is. I could get some data and come back
<dael> smfr: My only concerns is sites where they do that and browsers prop. the body background and you get a flash of color change
<dael> emilio: Body background is spec to not prop if there's display:none
<dael> smfr: I guess Chrome has a bug that it doesn't do that which is shared by WK
<dael> emilio: Def Chrome, I don't know WK
<dael> smfr: Prob does. I don't feel too strongly. Seems reasonable
<dael> plinss: Curiousabout usage of display:none body. I can see it abused for tracking iframes and whatnot on a page. Curious if that's something people want to do.I guess if they're putting in iframe they won't put a bg on it
<bkardell_> but changing -- there isn't interop now -- or is there?
<dael> plinss: Prop: Not prop any style from display:none HTML or Body
<dael> emilio: Don't propagate the background of the element...basically whatever definition the background propagation is using I want to align
<dael> plinss: Objections?
<dael> RESOLVED: Do not propagate any style from display:none HTML or Body

[css-overflow-3] Do not propagate overflow from boxless elements.

Handle display:contents for viewport propagation.

Bug 1540220 - Remove some useless usage of LazyComputeBehavior::Allow…

Bug 1568525 [wpt PR 18039] - Handle display:contents for viewport pro…

Bug 1568536 - Don't propagate viewport styles from display: none or d…

Bug 1540220 - Remove some useless usage of LazyComputeBehavior::Allow…

Bug 1568525 [wpt PR 18039] - Handle display:contents for viewport pro…

Bug 1568536 - Don't propagate viewport styles from display: none or d…

[css-overflow-3][css-backgrounds-3][css-writing-modes] Don't propagat…

Bug 1540220 - Remove some useless usage of LazyComputeBehavior::Allow…

Bug 1568525 [wpt PR 18039] - Handle display:contents for viewport pro…

Bug 1568536 - Don't propagate viewport styles from display: none or d…

Navigation Menu

Repository navigation

[css-overflow] Overflow propagation when the element propagated from is display: none #3779

15 remaining items

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

[css-overflow] Overflow propagation when the element propagated from is display: none #3779

Description

Activity

emilio commented on Mar 29, 2019

fantasai commented on Mar 29, 2019

lilles commented on Mar 31, 2019

lilles commented on Mar 31, 2019

lilles commented on Mar 31, 2019

lilles commented on Apr 1, 2019

css-meeting-bot commented on Apr 10, 2019

15 remaining items

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions