Update Combo Box When Change Made To Underlying Table

I have a form with a Combo box, populated from table A. From this list, the user can select a item for data entry into table B. If the desired item is not found in the combo box, the user can launch another form that will allow the item to be added to table A. However, when the user returns to the data entry form for table B, the new item doesn't appear in the combo box.

I saw this problem addressed in another posting, but the solution (which required code behind an Exit button) will only work if the data entry form for table B is open :eek: . So, if the user wants to only do data entry into table A, an error will be raised when they try to exit.

Other than creating a seperate data entry form strictly for table A, is there an easier way to update the combo box on the entry form for table B?

Thank you!!!!!!!!!!!