T_THERA - is a transaction table
    Columns: ID - STRING
             MR - STRING
             ITEMCODE - STRING
             QTY - INT
             SIGNA - TEXT
M_ITEMS - Masterfile of items
    Columns: ITEMCODE - STRING
M_SIGNA - Masterfile of Signa
    Columns: SIGNACODE - String
             DESCRIPTION - String

I have a DGV1 with retrieved data...

sql of DGV1 is something like "SELECT T.ID, M.DESCRPTION, T.QTY, T.SIGNA
                               FROM T_THERA T, M_ITEM M WHERE T.ITEMCODE = M.ITEMCODE AND 
                               T.MR = '"& AS_MR &"'"

I need to change the SIGNA column to a combobox. BUT the data in the combobox is a masterfile from another table (M_SIGNA).  The DGV1 is populated from another window with a selection of items (M_ITEMS).  If new items are inserted, the SIGNA (now a combobox) on T_THERA should be null and user can select the correct value from the populated combobox (M_SIGNA).

The user then should be able to save the transactions.

I have been looking for a better solution but to no avail.  I'm just losing hope on this!  Please share your ideas on how to go about my problem.