Private Sub Combo116_AfterUpdate()
    SetFilter
End Sub
 
Private Sub Combo118_AfterUpdate()
    SetFilter
End Sub
 
Private Sub Combo154_AfterUpdate()
    SetFilter
End Sub
 
Private Sub SetFilter()
    Dim strFilter As String

    If Not IsNull(Me.Combo116) Then
        strFilter = " AND BankLog = "

Private Sub Combo116_AfterUpdate()
    If IsNull(Me.Combo116) Then
        Me.FilterOn = False
    Else
        Me.Filter = "BankLog = """ & Me.Combo116 & """"
        Me.FilterOn = True
    End If
End Sub

[Forms]![Collections_MASTER]![Combo118] Or [Forms]![Collections_MASTER]![Combo118] Is Null

IIf([Forms]![Collections_MASTER]![Combo118] Is Not Null,[Forms]![Collections_MASTER]![Combo118])

=[Forms]![Collections_MASTER]![Combo118]