DescriptionValidationTable refusing to work

[Yannis]

Hello,
I am using a DescriptionValidationTable in a datadictionary, bound to a field in a table.
In a clean view using this table, created with the wizard, I have a combo for this field, but when I click on the arrow to open the combo, all I get is just a small blue-ish underline of the combo.
In the view, the combo as an object is correctly bound to the right field, and no sub classing is used.
The DescriptionValidationTable is declared in the datadictionary as follows (taken from the help):

Object Terms_table  is a DescriptionValidationTable
    Procedure Fill_List
        Forward Send Fill_List
        Send Add_Table_Value  "NONE"    "None established"
        Send Add_Table_Value  "COD"     "COD"
        Send Add_Table_Value  "NET30"   "Net 30"
        Send Add_Table_Value  "NET60"   "Net 60"
        Send Add_Table_Value  "NET90"   "Net 90"
        Send Add_Table_Value  "PREPAY"  "Pre-payment required"
    End_Procedure
End_Object

And then in the Construct object inside the DD, I use:

Set Field_Class_Name Field Ptyppar.Ptyppar_Is_What to "Combo"
Set Field_Value_Table Field Ptyppar.Ptyppar_Is_What to Terms_table
Set Status_Help Field Ptyppar.Ptyppar_Is_What to "Payment terms"

Any ideas as to why I can't see the options available?
(Using VDF19.1 / Windows10)

Yannis