LookupGrid: Fix error causing multiple entries in lookup control

Controls.LookupGrid/LookupControl3.vb

@@ -233,11 +233,13 @@ Public Class RepositoryItemLookupControl3
                     If oForm.NewValues.Count > 0 AndAlso TypeOf DataSource Is DataTable Then
                         Dim oTable As DataTable = DirectCast(DataSource, DataTable)
 
-                        For Each oValue In oForm.NewValues
-                            Dim oRow = oTable.NewRow()
-                            oRow.Item(0) = oValue
-                            oTable.Rows.Add(oRow)
-                        Next
+                        If oTable.TableName <> NAME_DATATABLE_INTERNAL Then
+                            For Each oValue In oForm.NewValues
+                                Dim oRow = oTable.NewRow()
+                                oRow.Item(0) = oValue
+                                oTable.Rows.Add(oRow)
+                            Next
+                        End If
                     End If
                 End If
             End Using