private void CityToolStripMenuItem_Click(object sender, EventArgs e)
        {
            City_Form cF = new City_Form(lastSelectedcomboBox_CityIndex);

            cF.StartPosition = FormStartPosition.CenterParent;
            cF.ShowDialog();
            CityArrToForm(cF.SelectedCity);

            lastSelectedcomboBox_CityIndex = (comboBox_City.SelectedItem as City);
        }
        private void comboBox_City_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (comboBox_City.SelectedItem != null)
            {
                if (comboBox_City.SelectedItem.ToString() == "+")
                {
                    if (comboBox_City.Focused)
                    {
                        City_Form cF = new City_Form(lastSelectedcomboBox_CityIndex);
                        cF.StartPosition = FormStartPosition.CenterParent;
                        cF.ShowDialog();
                        CityArrToForm(cF.SelectedCity);
                    }
                }

                lastSelectedcomboBox_CityIndex = (comboBox_City.SelectedItem as City);
            }
        }