Dialog not programmatically identified as modal (Settings dialog > Wallpaper category dialog)

Steps to Reproduce

Open DevTools. Activate the Customize button. Within the Settings dialog, activate a button representing a wallpaper category swatch (e.g., Abstract). Another dialog opens offering users various wallpaper designs. Inspect this dialog container.

Expected Behavior

Dialog container has aria-modal="true".

Actual Behavior

Dialog container lacks the aria-modal attribute.

User Impact

Semantic information diluted.

WCAG 2.2 References

Best practice only. While aria-modal="true" adds semantic information, its absence does not constitute a WCAG failure provided the dialog itself is properly implemented and announced.

Recommendations

Apply aria-modal="true" to the dialog container. This is the clearest, least fragile way to convey "this is modal" to screen readers.

Testing Environment

Any

Assistive Technology Used

Any

Code Pointers

<section class="category wallpaper-list ignore-color-mode wallpaper-list-enter-done" style="">

Further Reference

• W3C WAI APG: Modal Dialog Example

Reproduced with Firefox 148.0a1 (2025-12-31) on macOS 15 and Windows 10.
Marking this issue as new for engineering input.
Thank you!

This is a change in a view within existing "Settings" dialog and the focus is placed on the header (first focusable element of the new content), thus user is notified of the change by the announcement of the focused element ("{Abstract} button").

That's being said, when the bug 2008117 the structure of the "< Abstract" and similar buttons would be resolved, this bug should be re-evaluated to ensure the change in the content of the dialog is being communicated to assistive technology users appropriately.

Assigning the Severity value to align with the Accessibility severity, per discussions with :thecount and :marco