void parametersForm_FormClosed(object sender, FormClosedEventArgs e)
 {
     if (parametersForm != null)
     {
         parametersForm.Dispose();
         parametersForm = null;
     }
 }
 private void buttonParameters_Click(object sender, EventArgs e)
 {
     if ((parametersForm == null) && (modelControl != null))
     {
         parametersForm             = new AircraftParametersForm(modelControl.AirplaneModel.AirplaneControl.AircraftParameters);
         parametersForm.FormClosed += new FormClosedEventHandler(parametersForm_FormClosed);
     }
     if (parametersForm != null)
     {
         parametersForm.Show();
         parametersForm.BringToFront();
     }
 }