When AdapTable wants to provide a list of values for a column (e.g. in a column filter, or when building a query or in Bulk Update) it will first get the list from Server Lookups if that has been set.
If not then it will look for any Permitted Columns values for that column. These are set through the PermittedValuesColumns property in the User Interface section of Predefined Config.
Here we set 'hard-coded' Permitted Column Values for Contact and Employee columns so only this list of values is displayed in their Column Filters (and Query Builder).
For the Cust Ref. column we provide a function that will be evaluated each time the list is required; this allows you to get the values from your local store or via an external look-up.
Additionally we set an empty array [' '] for the Order Date Column so that NO distinct column values are diplayed, and only the System Filters for Date columns are shown.
Note: if there are no Permitted Values, then AdapTable will dynamically build a list of distinct values for the column.