Sub AddComboBox()
Application.ScreenUpdating = False
Dim objCC As ContentControl, StrTxt As String, i As Long
With Selection.Range
  If InStr(.Text, "[") = 0 Then Exit Sub
  If InStr(.Text, "]") = 0 Then Exit Sub
  If .Characters.Last <> "]" Then .MoveEndUntil "]", wdBackward
  StrTxt = .Text
  StrTxt = Replace(StrTxt, "]", "")
  .Text = vbNullString
  Set objCC = .ContentControls.Add(wdContentControlComboBox)
  With objCC
    .SetPlaceholderText Text:="Please make a selection"
    For i = 1 To UBound(Split(StrTxt, "["))
      .DropdownListEntries.Add Split(StrTxt, "[")(i)
    Next
  End With
End With
Application.ScreenUpdating = True
End Sub