1. What is the Row Source of your combo box?
2. Which field(s) is/are visible?
3. How about using the Allow Value List Edits and List Items Edit Form properties of the combo box? Much quicker to implement.
This adds to the field bound to the form not the underlying table/query (or Row Source) of the combo box. But then again, perhaps this is what the OP was trying to convey.
The row source has the 3 values in it that appear in the dropdown and the entire field (Institution) is visible. When I change allow values edits, limit to list, or list items edit form, I get the text entered isn't an item on the list and when I go to add it I get the linked table has been changed on the server, the last entry will not be saved. I do not want to add the entry to the list, rather save it to the individual record. Thanks.