I would put the values from the combo entry into textbox controls so as to be able to edit.
Those controls could be bound to the table or not.
Then requery the combo.
Save the entry, so you can go back to it after the requery.
Your application needs better flow. I've included a link to a tiny sample application which is an Address Book. It shows how you can both view and edit records. Your interface does not provide any way to edit existing records and you are struggling with that.
The letter buttons at the bottom of the form can be used to filter books as well as addresses and the department combo could be used to filter by category.