Used to fill the ComboBox with data created in the Niche or UD.
You have 3 options in the Fill Behavior, they are:
Manual: you need to put a DataRetriever manually before the ComboBox, if you don´t do this the ComboBox will be displayed blank.
AutoData: the DataRetriever is put automatically in the ComboBox.
AutoData Refresh: aside from DataRetriever being put automatically in the ComboBox, it refresh it self when using it. Very useful when the second ComboBox display itens according to what is select in the first ComboBox.