private void EditCmpRevData_Load(object sender, EventArgs e)
        {
            try
            {
                data = new CmpRevData(node.Tag as byte[]);
                if (data.Parts.Count == 0)
                {
                    throw new Exception("No parts");
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show("Error " + ex.Message, "Error");
                Close();
                return;
            }

            labelPartCount.Text = String.Format("of {0}", data.Parts.Count);
            partUpDown.Maximum  = data.Parts.Count;
            foreach (CmpRevData.Part part in data.Parts)
            {
                comboBoxChildName.Items.Add(part.ChildName);
            }
            comboBoxChildName.Select();
            partNumber = 0;
            DisplayPart();
        }