/********************************************************************
* Coordinate systems
* _coordSystem_form
********************************************************************/
        private void coordSystemopen(object sender, EventArgs e)
        {
            if (_coordSystem_form == null)
            {
                _coordSystem_form                = new ControlCoordSystem();
                _coordSystem_form.FormClosed    += formClosed_CoordSystemForm;
                _coordSystem_form.RaiseCmdEvent += OnRaiseCoordSystemEvent;
            }
            else
            {
                _coordSystem_form.Visible = false;
            }
            _coordSystem_form.Show(this);
            _coordSystem_form.WindowState = FormWindowState.Normal;
        }
 private void formClosed_CoordSystemForm(object sender, FormClosedEventArgs e)
 {
     _coordSystem_form = null;
 }