VoiceOver focus issue in Safari 26 modal dialogs (regression from Safari 18.4)

After upgrading to Safari Version 26, we observed an accessibility regression related to VoiceOver focus behavior when opening modal dialogs.

When a dialog is opened:

• Browser focus correctly moves to the first interactive element inside the dialog.
• However, VoiceOver focus remains on the button that triggered the dialog instead of shifting to the dialog content.

As a result:

• If the user presses VO + Left Arrow, they can navigate to and interact with content behind the modal, even though it shouldn't be accessible.
• If the user presses Tab, both browser and VoiceOver focus then synchronize correctly from that point onward, and normal navigation resumes.

This creates confusion for VoiceOver users, as they rely on focus announcements to understand context. When the dialog opens, VoiceOver continues reading the trigger button and allows navigation behind the modal, making it unclear that a new dialog has appeared.

Steps to Reproduce:

1. Open Safari 26.
2. Turn on VoiceOver.
3. Turn on Quick Nav if it’s not already enabled.
4. Navigate to and open the official W3C ARIA dialog example: https://www.w3.org/WAI/ARIA/apg/patterns/dialog-modal/examples/dialog/
5. Move focus to the “Add Delivery Address” button and activate it.
6. Observe VoiceOver’s focus and attempt to navigate using VO + Left Arrow.

Expected Behavior:

When a dialog opens, both browser focus and VoiceOver focus should move to the interactable content within the dialog, and content behind it should not be accessible.

This was the behavior in Safari 18.4.

Actual Behavior:

• VoiceOver stays focused on the trigger button.
• Background content can be accessed using VO navigation.
• Pressing Tab once fixes the focus alignment.

Additional Info:

• Safari version: 26
• VoiceOver: Default macOS VoiceOver
• Was working correctly in: Safari 18.4
• Reproducible on: W3C ARIA dialog example and other apps using standard ARIA dialog markup.

Here's the screen recording showing the behavior on the W3C example page: Link

[Re-Titled by Moderator]

Original Title: VoiceOver focus remains on trigger button when modal dialog opens in Safari 26 (regression from Safari 18.4)