Actually, I've figured out a different way.
On your form, place an unbound textbox and name it "txtName". Set it's Locked property to Yes so users can't edit it (should be read-only).
Place a combo-box on your form, which should start a Wizard. Go through following steps on the wizard:
(1) Choose the first option "...look up values in a table or query"
(2) Choose your Propects table as the table that provides your values
(3) Choose which fields you want in the dropdown. You will want your ID field, first_name and last_name
(4) Next step lets you say how to sort - I would guess you would sort by last_name
(5) At this step you get a preview of the list. The "Hide key column" should be checked by default
(6) On this step choose the option "store that value in the field" - and choose the foreign key to the Prospect table that you have in your Donations table
(7) Last step is just to give a label to the drop down
In the properties of the combo-box, make the Name="cboProspect".
Now you need to add some code for the form's Current event, the Dropdown's AfterUpdate event, plus a custom subroutine for displaying the name, as follows:
Code:
Private Sub cboProspect_AfterUpdate()
DisplayName
End Sub
Private Sub Form_Current()
If Me.NewRecord Then
txtName = ""
Else
DisplayName
End If
End Sub
Private Sub DisplayName()
If Not (IsNull(cboProspect)) Then
txtName = cboProspect.Column(1) & " " & cboProspect.Column(2)
End If
End Sub