Master/Child links on subforms (1 Viewer)

I have an interesting problem. I have two tables I'm using with a form that contains a subform. The first table is an enrollment table which contains a set of fields used as a primary key. Those fields are (in order): Institution, Year, Quarter, Item(a Class ID number) and SID (a Student ID number). This first table tracks which classes each student is enrolled.

The second table (which drives the subform) has the exact same primary key fields indexed in the exact same order, but tracks the students progress within a specific class.

The form allows the user to select a class and displays a "class roster" that shows each student along with their associated progress within the class. The Master form allows the user to choose the specific class while the sub form displays the students and their progress in a grid like fashion.

The Master/Child links I've set to be Institution, Year, Quarter, Item. However, whenever I go in to modify the subform (i.e. add a control or change a control's attribute) the links change to Institution, Year, Item, SID.

Any ideas on what might be causing this change to take place and how I can prevent it?

Thanks

Dave

Never mind. I figured it out. It looks like the Master and Child linking fields have to be spelled the same. In my tables one spelled Quarter as Qtr and that seemd to throw everything off. Once I changed the errant field's name to Quarter then things went fine. Duh! <hangin head in shame, not realizing that spelling counts>.