You need to add action on the field CUNLISDET to fill up newly created field.

Thank you for the answer , actually the cunlisdet is the table of stock count  , i already test (aprés _modif , MODIF ) actions on the field  and still having the  same issue but for saving data in the table as i mentioned i used an entry point  , i believe there is another screen load  SNL0 like SIW or something ???