Re: [csswg-drafts] [css-position] overlay property UA sheet is not enough. (#11194)

The CSS Working Group just discussed `[css-position] overlay property UA sheet is not enough.`, and agreed to the following:

* `RESOLVED: UAs must apply 'overlay: none !important' to all pseudo-elements`

<details><summary>The full IRC log of that discussion</summary>
&lt;fantasai> TabAtkins: I think for this issue we should resolve to "figure out how to fix this". But it absolutely was an unintentional allowance.<br>
&lt;fantasai> TabAtkins: overlay property, which allows things to leave top layer, is only settable on a few things<br>
&lt;fantasai> TabAtkins: by default, UA stylesheet has 'none !important'. Can only use in transition property, can't actually set the property<br>
&lt;fantasai> TabAtkins: But UA stylesheet only uses *<br>
&lt;fantasai> TabAtkins: which leaves out pseudos<br>
&lt;fantasai> TabAtkins: We don't have a way to generically refer to pseudo-elements<br>
&lt;oriol> q+<br>
&lt;fantasai> TabAtkins: So leave it open to figure out the solution, but we should resolve that this is unintentional and author's can't set it on pseudo-elements<br>
&lt;astearns> ack oriol<br>
&lt;fantasai> oriol: In another issue, 7346, we resolved to add some kind of ? to work on it<br>
&lt;fantasai> oriol: syntax that would allow using *:&lt;&lt;* and this would select all pseudo-elements that are originated and would selected all possible pseudo-elements<br>
&lt;TabAtkins> `:>>` being the "pseudo-tree combinator"<br>
&lt;fantasai> oriol: we could use it here<br>
&lt;oriol> *, * :>> * { overlay: none !important }<br>
&lt;fantasai> oriol: more work to do but it's something<br>
&lt;astearns> ack fantasai<br>
&lt;TabAtkins> fantasai: can we just resolve here that the ua stylesheet must apply this to * and to all pseudos? and let the ua figure out how to do it<br>
&lt;TabAtkins> astearns: we have in the past discussed whether it should be possible to express something in the UA stylesheet that cna't be expressed in author land, and decided that it's bad<br>
&lt;TabAtkins> fantasai: you can do it in author land, just list all pseudo-elements explicitly. we just shoudln't be maintaining that list.<br>
&lt;fantasai> astearns: proposed that overlay: none !important also applies to all pseudos<br>
&lt;fantasai> RESOLVED: UAs must apply 'overlay: none !important' to all pseudo-elements<br>
</details>


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Received on Tuesday, 1 April 2025 20:56:04 UTC