If you click elsewhere presumably that would make this not accessible - we'd need some sort of escape action and maybe trapped focus?

Not really sure. It should work the same as a drop-down select. I think

The specification for a list is here https://www.w3.org/TR/wai-aria-practices/examples/listbox/listbox-collapsible.html

From what I can tell there are two issues that perhaps have the same fix

A select list should change the value immediately (it does) and then you press enter to confirm (it does) and that technically you can not undo a change so there is no escape to close.

However the issue is that you can not "select" the existing value. If you could then the issue would probably be resolved. However there might be consequences to someones workflow as it might trigger an event?

@wilsonge I think it might be able to be fixed in a much easier way. Currently the select is built using ContentHelper::filterTransitions

If that is changed so that the list is not filtered then it should work. (I don't know how but I am sure you do)

Still an issue with the new workflows

There is no way to click away from the opened list to close it. I am guessing there needs to be some js for this

// eventListener to select item
on click inside the list
select item and close the list

// eventListener to close the div
on click outside the list
close the list

@bembelimen can you have a look at this?

Any reason why a close button would not work?

[select][x]

no - that would be fine although might be a bit ugly