John the Me.Requery in afterupdate did not help.
To simplfy the matter, I got rid of the combo box with the ordinary bound control for the master control link. The field for the master is from a parameter query (to allow selecting specific records) which in turn is an indexed (no duplicates)...
My mainform is based on a table and serves to update the table fields. The subform is based on a query that has calculated fields in it. The subform serves to provide read only information and is set as enable - 'no', locked - 'yes'
The master link field is configured as a combo control (to...