Select multiple values from an Excel dropdown list?

Question

Online search suggested I use below VBA code to enable multiple selections in MS Excel dropdown list, save as Macro-Enabled and it should work. However, it's not working. Can you help?

'Code by Sumit Bansal from https://trumpexcel.com
' To allow multiple selections in a Drop Down List in Excel (without repetition)
Dim Oldvalue As String
Dim Newvalue As String
Application.EnableEvents = True
On Error GoTo Exitsub
If Target.Column = $G$ Then
If Target.SpecialCells(xlCellTypeAllValidation) Is Nothing Then
GoTo Exitsub
Else: If Target.Value = "" Then GoTo Exitsub Else
Application.EnableEvents = False
Newvalue = Target.Value
Application.Undo
Oldvalue = Target.Value
If Oldvalue = "" Then
Target.Value = Newvalue
Else
If InStr(1, Oldvalue, Newvalue) = 0 Then
Target.Value = Oldvalue & ", " & Newvalue
Else:
Target.Value = Oldvalue
End If
End If
End If
End If
Application.EnableEvents = True
Exitsub:
Application.EnableEvents = True
End Sub

Private Sub Workbook_Open()

End Sub

Answer 1

Sorry for the late response. I just read your question. Hopefully this works for you:

Private Sub Worksheet_Change(ByVal Target As Range)

Dim rngDV As Range
Dim oldVal As String
Dim newVal As String
Dim colLabel As String
Dim strMatch As String
Dim nbrRow As Integer

If Target.Count > 1 Then GoTo exitHandler

nbrRow = ActiveCell.Row

If nbrRow = 1 Then GoTo exitHandler

Set rngDV = Cells.SpecialCells(xlCellTypeAllValidation)
If rngDV Is Nothing Then GoTo exitHandler

' get current column's label, from row 1
colLabel = Cells(1, Target.Column)
strMatch = Left(colLabel, 8)
If strMatch <> "Session " Then GoTo exitHandler

On Error Resume Next
Set rngDV = Cells.SpecialCells(xlCellTypeAllValidation)
On Error GoTo exitHandler

If rngDV Is Nothing Then GoTo exitHandler

If Intersect(Target, rngDV) Is Nothing Then
   'do nothing
Else:
  Application.EnableEvents = False
  newVal = Target.Value
  Application.Undo
  oldVal = Target.Value
  Target.Value = newVal
    If oldVal = "" Then
        'do nothing
    Else
      If newVal = "" Then
        'do nothing
      Else
        Target.Value = oldVal _
        & Chr(10) & newVal
      End If
    End If
End If

exitHandler:
  Application.EnableEvents = True
End Sub