Hello

I've noticed a bug specific to Safari. When using VoiceOver, I'm able to send a click event (VO+Space) to an element with the role="combobox" attribute only when it does not have the aria-expanded attribute. Once the attribute is set, regardless of its value, the click action does not work. I'm able to send the click event for comboboxes with aria-expanded in Chrome and Firefox.

See the live example of a select only combobox in the ARIA authoring practices- https://www.w3.org/TR/wai-aria-practices-1.2/examples/combobox/combobox-select-only.html
If you remove the aria-expanded="false" from the element in the web inspector and try sending the click- it will work- the listbox popup will expand.

Some other notes:
- it seems that Safari is treating an element with role="combobox" and aria-expanded="false" as if it was expanded as it begins the announcement with the word "confirm",
- aria-expanded is a required state as per the ARIA spec (https://www.w3.org/TR/wai-aria-1.1/#combobox) meaning that it must be present at all times
- the issue will be highly problematic once ARIA 1.2 turns into a recommendation (currently in candidate recommendation meaning it is close to become the spec) as 1.2 officially acknowledges comboboxes as select-only and text field comboboxes whereas previous versions were treating this element as if it always had to have a text box.

Alos, see the attached aria-ExpandedComboboxIssue.html file that shows the issue but displaying the system alert dialog on click.