New Combobox Item in Oracle APEX 23.2
Oracle APEX 23.2 introduces the new Combobox Item Type which supports selecting multiple values at once without closing the list of values and groups within the list of values. The HTML expression supports template directives and substitution strings. The Combobox also supports multi-column search.
Try this and other new features in APEX 23.2 on https://apex.oracle.com