It seems we have some issues in the EuiComboBox, that the label shown when your query doesn't match any item in the list.

Earlier we could see a message like "Hit Enter to create that item" in the popover. It seems that code still exists: https://github.com/elastic/eui/blob/master/src/components/combo_box/combo_box_options_list/combo_box_options_list.tsx#L223:L254

But it's never triggered, because the usage of the EuiComboBoxOptionsList actually never set the getSelectedOptionForSearchValue property which would be required to reach that code part.

I am not sure when or how that behavior got lost, but it would be nice if that message would be shown to clarify that items in the combo box can be created, when hitting enter.