private void buttonExtConfigure_Click(object sender, EventArgs e)
        {
            System.Diagnostics.Debug.Assert(last_si != null);           // must be set for this configure button to be visible

            ExtendedControls.ConfigurableForm f = new ExtendedControls.ConfigurableForm();

            int width    = 430;
            int ctrlleft = 150;

            f.Add(new ExtendedControls.ConfigurableForm.Entry("L", typeof(Label), "Fuel Warning:".T(EDTx.UserControlModules_FW), new Point(10, 40), new Size(140, 24), ""));
            f.Add(new ExtendedControls.ConfigurableForm.Entry("FuelWarning", typeof(ExtendedControls.NumberBoxDouble),
                                                              last_si.FuelWarningPercent.ToString(), new Point(ctrlleft, 40), new Size(width - ctrlleft - 20, 24), "Enter fuel warning level in % (0 = off, 1-100%)".T(EDTx.UserControlModules_TTF))
            {
                numberboxdoubleminimum = 0, numberboxdoublemaximum = 100, numberboxformat = "0.##"
            });

            f.Add(new ExtendedControls.ConfigurableForm.Entry("Sell", typeof(ExtendedControls.ExtButton), "Force Sell".T(EDTx.UserControlModules_ForceSell), new Point(10, 80), new Size(80, 24), null));

            f.AddOK(new Point(width - 100, 110), "Press to Accept".T(EDTx.UserControlModules_PresstoAccept));
            f.AddCancel(new Point(width - 200, 110), "Press to Cancel".T(EDTx.UserControlModules_PresstoCancel));

            f.Trigger += (dialogname, controlname, tag) =>
            {
                if (controlname == "OK")
                {
                    double?v3 = f.GetDouble("FuelWarning");
                    if (v3.HasValue)
                    {
                        f.ReturnResult(DialogResult.OK);
                    }
                    else
                    {
                        ExtendedControls.MessageBoxTheme.Show(this.FindForm(), "A Value is not valid".T(EDTx.UserControlModules_NValid), "Warning".T(EDTx.Warning), MessageBoxButtons.OK, MessageBoxIcon.Error);
                    }
                }
                else if (controlname == "Cancel" || controlname == "Close")
                {
                    f.ReturnResult(DialogResult.Cancel);
                }
                else if (controlname == "Sell")
                {
                    if (ExtendedControls.MessageBoxTheme.Show(FindForm(), "Confirm sell of ship:".TxID(EDTx.UserControlModules_ConfirmForceSell) + Environment.NewLine + last_si.ShipNameIdentType, "Warning".T(EDTx.Warning), MessageBoxButtons.YesNo, MessageBoxIcon.Warning) == DialogResult.Yes)
                    {
                        var je = new EliteDangerousCore.JournalEvents.JournalShipyardSell(DateTime.UtcNow, last_si.ShipFD, last_si.ID, 0, EDCommander.CurrentCmdrID);
                        var jo = je.Json();
                        je.Add(jo);
                        discoveryform.NewEntry(je);
                    }

                    f.ReturnResult(DialogResult.Cancel);
                }
            };

            DialogResult res = f.ShowDialogCentred(this.FindForm(), this.FindForm().Icon, "Ship Configure".T(EDTx.UserControlModules_SC), closeicon: true);

            if (res == DialogResult.OK)
            {
                last_si.FuelWarningPercent = f.GetDouble("FuelWarning").Value;
                Display();
            }
        }