private void _okButton_Click(object sender, EventArgs e)
            {
                object[] bufferNodes = new object[_treeView.Nodes.Count];

                for (int i = 0; i < bufferNodes.Length; i++)
                {
                    bufferNodes[i] = _treeView.Nodes[i].Clone();
                }

                base.Items = bufferNodes;

                _treeView.Dispose();
                _treeView = null;
            }