private void btnTimeSlot_Click(object sender, EventArgs e) { if (TimeslotDockWindow == null) { TimeslotDockWindow = new DocumentWindow(); TimeslotDockWindow.CloseAction = DockWindowCloseAction.Close; fmTimeSlotList = new frmTimeSlotList(); fmTimeSlotList.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None; fmTimeSlotList.TopLevel = false; fmTimeSlotList.Dock = DockStyle.Fill; TimeslotDockWindow.Text = fmTimeSlotList.Text; TimeslotDockWindow.Controls.Add(fmTimeSlotList); this.radDock1.AddDocument(TimeslotDockWindow); fmTimeSlotList.Show(); } else { TimeslotDockWindow.Show(); } this.radDock1.ActiveWindow = TimeslotDockWindow; }