Steps to reproduce the issue

1.with any date field eg Start publishing navigate to the calendar icon and press enter to open the popup
2. using the arrow keys to select a date
3. when you have navigated to the correct date
4. select the date by pressing enter or space

Version

5.4

Expected result

The selected date is displayed in the field

Actual result

no date is selected when you press enter
the alternative of using the space key just puts a space in the date field and leeps the selector open

What device were you using? (eg, phone, laptop)

windows 11

What web browser were you using? (eg, Chrome, Safari)

Chromium

Assistive Technology?

keyboard

Additional Comments

An example of how i expted it to work
https://www.w3.org/WAI/ARIA/apg/patterns/dialog-modal/examples/datepicker-dialog/

it is also not possible as a keyboard user to navigate to anything other than the days of the month - you are restricted to navigating inside the highlighted area