public static void Sluit_form(base_form enkel_sluit)
        {
            base_form tmpfrm;

            if (Forms_OD.Contains(enkel_sluit))
            {
                tmpfrm = (base_form)Forms_OD[enkel_sluit];
                enkel_sluit.program_closes = true;
                enkel_sluit.Close();
                Forms_OD.Remove(enkel_sluit);

                String log_line             = "sluit venster @ " + DateTime.Now.ToString() + ": huidig: " + enkel_sluit.ToString() + ": close_naar: " + tmpfrm.ToString();
                System.IO.StreamWriter file = new System.IO.StreamWriter(Global.log_file_path, true);
                file.WriteLine(log_line);
                file.Close();
            }
        }
        public static void Sluit_forms(base_form sluit_vanaf)
        {
            DE = Forms_OD.GetEnumerator();
            int       index          = 0;
            bool      gevonden       = false;
            base_form herlaad_scherm = new base_form();

            while (DE.MoveNext())
            {
                if (DE.Key == sluit_vanaf && !gevonden)
                {
                    herlaad_scherm = (base_form)Forms_OD[index];
                    KillStack.Push((base_form)DE.Key);
                    gevonden = true;
                }
                else if (gevonden)
                {
                    KillStack.Push((base_form)DE.Key);
                }

                ++index;
            }
            int KillCount = KillStack.Count;

            for (int j = 0; j < KillCount; j++)
            {
                base_form tmp = KillStack.Pop();

                if (Sluitbaar(tmp))
                {
                    Forms_OD.Remove(tmp);
                    tmp.program_closes = true;
                    tmp.Close();
                    String log_line             = "sluit venster @ " + DateTime.Now.ToString() + ": huidig: " + tmp.ToString() + ": close_naar: " + herlaad_scherm.ToString();
                    System.IO.StreamWriter file = new System.IO.StreamWriter(Global.log_file_path, true);
                    file.WriteLine(log_line);
                    file.Close();
                }
                else
                {
                    herlaad_scherm = tmp;
                    break;
                }
            }

            if (gevonden)
            {
                herlaad_scherm.herlaad();
            }
            KillStack.Clear();
        }
        public static void VoegToe(base_form huidig, base_form sluit_naar)
        {
            Forms_OD.Add(huidig, sluit_naar);
            String log_line = "open venster @ " + DateTime.Now.ToString() + ": huidig: " + huidig.ToString() + ": close_naar: " + sluit_naar.ToString();

            System.IO.StreamWriter file = new System.IO.StreamWriter(Global.log_file_path, true);
            file.WriteLine(log_line);
            file.Close();
        }