bug(mat-chip-listbox): fails on accessibility score

[aalbericio]

Is this a regression?

• Yes, this behavior used to work in the previous version

The previous version in which this bug was not present was

No response

Description

Whenever I use "mat-chip-listbox", I can't make it score 100% on Lighthouse. It always complains about roles of children, etc.

The same code can be changed to use a "mat-chip-grid" and everything works as expected (scores 100%), so there must be something in this component (or subcomponents like mat-chip-option) that is not really working for accessibility.

Reproduction

StackBlitz link: https://stackblitz.com/edit/6mumju4m-rs7e6l4g?file=src%2Fexample%2Fchips-autocomplete-example.html

Steps to reproduce:

1. Run the application in external mode and run a Lighthose accessibility-only report.
2. Get 21/22 points and some complaints about accessibility

Expected Behavior

I would expect to work as mat-chip-grid (with mat-chip-rows) that score a 100%.

Actual Behavior

Score is 21/22 with some complaints about :

Elements with an ARIA [role] that require children to contain a specific [role] are missing some or all of those required children.

Environment

• Angular: 19.2.0
• CDK/Material: 19.2.17 (same example as Angular Material official website)
• Browser(s): Chrome
• Operating System (e.g. Windows, macOS, Ubuntu): Windows

[crisbeto]

This is because you're using matChipRemove with the listbox, but it's actually meant for the chip grid. A remove button doesn't make sense inside a selectable chip.

[aalbericio]

Hi @crisbeto ,

I probably misunderstood the use-cases for mat-chip-listbox and mat-chip-option but this is extracted from the offcial Angular Material documentation:

https://material.angular.dev/components/chips/overview#remove-button

Indeed, it works perfectly well except from the accessibility score that I mentioned.

If you can't fix that, is there any recommendation I should follow, in my scenario, to increase the accessibility score?

Thanks in advance.

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