Removing elements from a local data structure effects the parent object

var dataTable = new DataTable();
dataTable.Columns.Add("Id", typeof(Int32));
dataTable.Columns.Add("ParentId", typeof(Int32));
dataTable.Columns.Add("Name", typeof(String));
dataTable.Rows.Add(new Object[] { 1, 0, "A" });
dataTable.Rows.Add(new Object[] { 2, 1, "B" });
dataTable.Rows.Add(new Object[] { 3, 1, "C" });
dataTable.Rows.Add(new Object[] { 4, 0, "D" });
dataTable.Rows.Add(new Object[] { 5, 4, "E" });

class Item {

  public Int32 Id { get; set; }

  public String Name { get; set; }

  public IEnumerable<Item> Children { get; set; }

}

IEnumerable<DataRow> GetChildren(DataTable dataTable, Int32 parentId) {
  return dataTable
    .Rows
    .Cast<DataRow>()
    .Where(row => row.Field<Int32>("ParentId") == parentId);
}

Item CreateItem(DataTable dataTable, DataRow row) {
  var id = row.Field<Int32>("Id");
  var name = row.Field<String>("Name");
  var children = GetChildren(dataTable, id)
    .Select(r => CreateItem(dataTable, r))
    .ToList();
  return new Item { Id = id, Name = name, Children = children };
}

IEnumerable<DataRow> GetTopLevelRows(DataTable dataTable) {
  return dataTable
    .Rows
    .Cast<DataRow>()
    .Where(row => row.Field<Int32>("ParentId") == 0);
}

var items = GetTopLevelRows(dataTable)
  .Select(row => CreateItem(dataTable, row))
  .ToList();

$(function(){

$('#add').click(function(){
  var myWritting = $('#textarea').val();
    $('#textarea').val('');
  $('#content').append( '<p>' + myWritting +'<input type="submit" value="delete" class="hide"/></p>')
});

  $('body').on('click', '.hide', function() {
    $(this).parent().remove();
    return false;
});

});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<button id="add">Add</button>
<textarea  id="textarea"></textarea>
<div id="content"></div>