Hi! I am opening this issue to ask about a different behaviour between the select-only and editable combobox elements.

The behaviour in question: highlight an item with keyboard, so it stays highlighted, then mouse click outside the list (basically do a blur by mouse).

select-only combobox selects the highlighted item.
autocomplete combobox does not select the highlighted item.

Is there a specific reason to have a different behaviour between them? I would expect that the behaviour is the same, and the behaviour should be not to select the highlighted item on mouse blur. I would, however, expect the highlighted item to be selected when blurring by Tab, but this works correctly, so no further action here.

Autocomplete: https://www.w3.org/WAI/ARIA/apg/patterns/combobox/examples/combobox-autocomplete-list/
Select Only: https://www.w3.org/WAI/ARIA/apg/patterns/combobox/examples/combobox-select-only/

What do you think? As always, I'm happy to help with a PR to fix if we agree on the correct behaviour. Thank you!