New to ADP

[vlree]

I have an access .mdb file that has code in the LimitToList and OnDoubleClick events.
NotInList

Private Sub Combo52_NotInList(NewData As String, Response As Integer)
    MsgBox "Double-click this field to add an entry to the list."
    Response = acDataErrContinue
End Sub

OnDoubleClick

Private Sub Combo52_DblClick(Cancel As Integer)
On Error GoTo Err_ORGName_DblClick
    Dim ORGName As String
    
    If IsNull(Me![Combo52]) Then
        Me![Combo52].Text = ""
    Else
        ORGName = Me![Combo52]
        Me![Combo52] = Null
     End If

    DoCmd.OpenForm "frmOrgNames", , , , , acDialog, "GotoNew"
    Me![Combo52].Requery
'    If ORGName <> 0 Then Me![Combo52] = ORGName
If (IsNull(ORGName) Or ORGName <> "") Then Me![Combo52] = ORGName
      
Exit_Combo52_DblClick:
    Exit Sub

Err_ORGName_DblClick:
    MsgBox Err.Description
    Resume Exit_Combo52_DblClick
End Sub

I would like to be able to do the same thing in a .adp file I am making. If not in list double click to add new item to underlying table. I am not getting it. The .adp is very different. I would appreciate some patient soul bearing with me. While I have done quite a bit in Access this is very different. thanks.