Use the Values settings directly.
Such as a data window DW_1, the data window column column col_week is the drop-down list box format,
Monday (value 1)
Tuesday (value 2)
If you want to add a value of 3 Wednesday, you only need to set the values with the following statement.
DW_1.Object.col_week.values = String (dw_1.object.col_week.values) "Wednesday" "~ T" "3" "/"
In fact, you can see a drop-down frame consisting of four parts. Such as right display field separator (tab value) true value "/"
You can freely set it.