private void add_tester(object sender, RoutedEventArgs e)
        {
            AddTester mytester = new AddTester();

            mytester.ShowDialog();
            testers_list.Items.Refresh();
        }//call the add tester window
        /// <summary>
        /// This function adds a new tester when we press on the button "Add Tester"
        /// This is a sighnup function for a click event
        /// </summary>
        /// <param name="sender">Who is sensing the event</param>
        /// <param name="e">Details of the event occurred</param>
        private void TesterAddButton_Click(object sender, RoutedEventArgs e)
        {
            AddTester addTesterWind = new AddTester();

            addTesterWind.ShowDialog();
        }
        private void button_Click(object sender, RoutedEventArgs e)
        {
            var window = new AddTester();

            window.ShowDialog();
        }