bug(Dialog): Dialog loses focus when it doesn't contain any focusable elements

[sciambalala]

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

Tab and Shift + Tab move focus outside the dialog when there are no focusable elements inside it.

Reproduction

StackBlitz link: https://stackblitz.com/edit/3l8tbmvh?file=src%2Fexample%2Fcdk-dialog-data-example.ts
Steps to reproduce:

1. Navigate to the "Open dialog" button with the keyboard and press Enter.
2. Press either Tab or Shift + Tab.

Expected Behavior

Tab and Shift + Tab do not move focus outside the dialog.

Actual Behavior

Tab and Shift + Tab move focus outside the dialog.

Environment

• Angular: v22
• CDK/Material: v22
• Browser(s): any
• Operating System (e.g. Windows, macOS, Ubuntu): any

[crisbeto]

This would be resolved by #24868, although it has been tricky to land internally.

[sciambalala]

This would be resolved by #24868, although it has been tricky to land internally.

Adding the inert attribute on the root node wouldn't completely solve the issue: focus would still move out of the page and land outside the content window. Is this something that was taken into consideration?

@crisbeto

[crisbeto]

It's not, but it's also not recommended to have a dialog without any focusable elements either.

[sciambalala]

By using only the inert attribute, the focus won't be trapped within the dialog even if it does contain focusable elements.
Moreover, I believe an alert dialog used to annouce a redirect to another page falls within the category of dialogs that may not contain focusable elements.

I understand that this may not be a bug that you intend to fix, but wouldn't it at least be worth a deeper look into the issue you mentioned?
@crisbeto

[crisbeto]

Ah okay, I was under the impression that in this case we would restore focus to the dialog container, but that's not what is happening. We only set focus on the container when the dialog is opened for the first time. I've sent #33654 to resolve it.