Hi Dennis,
This is strange as it has always worked for me. The primary key index of the parent should be identical to the foreign key index of the child. You can open the table object in the DBC with the modify command to see if the indexes are the same.
If both parent and child fields are numberic with width of 8, I could create and index named the_clientno on field clientno in parent, and an index named the_cno on field cno in child.
Then I could go to the bottom of the table object diagram looking under label named "Index" for the_clientno index. I could grab it and drag it into the child table object diagram to link the_clientno into child index the_cno. After linking, there will be a line drawn between the two tables linking the_clientno and the_cno indexes. Also, a "Key picture" icon will appear in the parent table next to the the_clientno index indicating the_clientno index in parent table is a primary key persistent relation into the child table's foreign key named cno via its the_cno index.
LelandJ