protected override void WndProc(ref Message m) { if (m.Msg == winuser_h.WM_SYSCOMMAND && notifyWindow != null) { if (m.WParam.ToInt32() == winuser_h.SC_MINIMIZE) { notifyWindow.Owner = null; this.InvokeIfRequired(() => Win32ApiHelper.ShowWindow(Handle, winuser_h.SW_HIDE)); ShowInTaskbar = false; } if (m.WParam.ToInt32() == winuser_h.SC_RESTORE) { notifyWindow.Owner = null; notifyWindow.WindowState = FormWindowState.Normal; } } base.WndProc(ref m); }