You may try to use onCellChanged event to control the selected value of an edited cell. docs.dhtmlx.com/doku.php?id=dhtm … ellchanged
After that you need to fill the second column with needed options:
combo.put(value,label) - adds a new record in the collection;
combo.remove(value) - removes a record from the collection;
combo.clear() - removes all records from the collection;