[css-pseudo-4] Layering of highlight pseudo backgrounds

[fantasai]

Currently the spec specifies that e.g. if ::selection and ::spelling-error and ::grammar-error all apply to the same piece of text and each specifies a background color, these are layered, which will be noticeable if any of them are semi-transparent.

Just want to confirm that this is the model we want. (The alternative would be that only the topmost color paints, unless it is the keyword transparent or something.)

[megangardner]

I believe that is what we want. I would also say that we would want that behavior of layering between custom highlights and ::spelling-error ::grammar-error and ::selection as well.

[tabatkins]

Confirm that I think this is what we want. If the pseudos partially overlap, it's valuable to be able to see the distinct boundaries (if the page caters to this by using partially-transparent colors)

[css-meeting-bot]

The CSS Working Group just discussed . [css-pseudo-4] Layering of highlight pseudo backgrounds, and agreed to the following:

• RESOLVED: Close no change

The full IRC log of that discussion

<dael> Topic:. [css-pseudo-4] Layering of highlight pseudo backgrounds
<dael> github: https://github.com//issues/4626
<dael> fantasai: confiming we want them to stack and layer. If yes we'll close no change
<dael> AmeliaBR: Makes sense for a selection on top of a spelling error
<dael> AmeliaBR: Looks as a highlight on top of what you've got
<dael> fantasai: It's on top of what you've got in element tree. It's multiple highlights
<dael> AmeliaBR: If you do red for spelling and transparent yellow for selection makes sense to stack
<dael> dbaron: Fine as long as spec which is on top
<dael> fantasai: Yep.
<dael> bkardell_: Is that a question we can ask devs what they expect?
<dael> fantasai: Seems everyone agrees we should layer. If there's an argument to not we can discuss
<dael> smfr: Apple requires layer
<dael> fantasai: Objections?
<dael> Rossen_: Objections to close no change?
<dael> RESOLVED: Close no change