void planAppointItemSeen(object sender, EventArgs e)
        {
            if (SelectedPlanAppoint != null)
            {
                SeenParameters parameters = new SeenParameters();
                parameters.Database    = Database;
                parameters.PlanAppoint = SelectedPlanAppoint;

                bgSetAppointSeen.RunWorkerAsync(parameters);
            }


            appointListTree.SelectedNode.NodeFont = new Font(appointListTree.SelectedNode.NodeFont, FontStyle.Regular);
        }
        private void bgSetAppointSeen_DoWork(object sender, DoWorkEventArgs e)
        {
            SeenParameters parameters = (SeenParameters)e.Argument;

            parameters.PlanAppoint.SetSeen(parameters.Database);
        }