Private Sub Worksheet_Change(ByVal giatri_chon As Range)

    'Updated by Extendoffice 20240118 - Vietnamese version

    Dim giatri1, giatri2 As String

    Dim kytu_ngancach As String

    Dim vung_dulieu, vung_chon As Range

    Set vung_dulieu = Me.UsedRange

    kytu_ngancach = ", "

    If giatri_chon.Count > 1 Or Intersect(giatri_chon, vung_dulieu) Is Nothing Then Exit Sub

    On Error Resume Next

    Set vung_chon = vung_dulieu.SpecialCells(xlCellTypeAllValidation)

    If vung_chon Is Nothing Then Exit Sub

    Application.EnableEvents = False

    giatri2 = giatri_chon.Value

    Application.Undo

    giatri1 = giatri_chon.Value

    giatri_chon.Value = giatri2

    If giatri1 <> "" And giatri2 <> "" Then

        If Not (giatri1 = giatri2 Or _

                InStr(1, giatri1, delimiter & giatri2) > 0 Or _

                InStr(1, giatri1, giatri2 & delimiter) > 0) Then

            giatri_chon.Value = giatri1 & kytu_ngancach & giatri2

        Else

            giatri_chon.Value = giatri1

        End If

    End If

    Application.EnableEvents = True

    On Error GoTo 0