Hi Cetin,
It is the other way around...

In my description ORDERS table would be TRANS, and CUSTOMERS would be MAST.
The relation would be from ORDERS into CUSTOMERS on CUSTOMERID (CUSTOMERS table ordered on the Primarykey).

If you have a grid with orders on the form, and a textbox bound to CUSTOMERS.CUSTOMERID, as you arrow down trough ORDERS the text box will not show the right ID and the record pointer does not move (unless you click in the textbox).
If now you add a grid on CUSTOMERS table to the form all looks right.

Do you see the same thing?