If list boxes are to be layered, i.e. made dependent on each other so that the next list box displays only those entries that match the previous list box, you can proceed as follows:
In the selected applet, you must create a relation between the base field of the first list box (starting point of the relation) and the corresponding field (foreign key) in the Allowed values dv of the dependent list box (reference).
Then you have to define two more properties for the base field of the first list box by setting the following :
Postback=true and onChange=>”Base_Field_Dependent_Listbox”.SetNull() .
In the selected applet, you must create a relation between the base field of the first list box (starting point of the relation) and the corresponding field (foreign key) in the Allowed values dv of the dependent list box (reference).
Then you have to define two more properties for the base field of the first list box by setting the following :
Postback=true and onChange=>”Base_Field_Dependent_Listbox”.SetNull() .