XTREE supports list substitution style (aka INFLD ||L) combo lists via the new ListX= and CellListX= clauses.
ListX = <code>, <descr>, <code>, <descr>,...
CellListX = <idx>, <code>, <descr>, <code>, <descr>,...
e.g.
ListX=1,UPS Ground,2,UPS BLUE,3,Fed Ex,4,Mail"
CellListX=c,AL,Alabama,CA,California,LA,Lower Alabama~~"
ListX and CellListX are just like List and CellList, respectively, except that the list of items consists of <code>,<descr> pairs, where the <code> is what you store in your application (and in the data and answer arrays) while the <descr> is what displays in XTREE. The concept and implementation is essentially the same as the INFLD ||L "list substitution" field type.
See sample programs XTRA5 and XTRA5C in the EXLIB for examples of using these clauses. Also see "Dropdown lists" Mouse and Keyboard.
Also: the following note—see List for others—is deemed sufficiently important to repeat here: