private void DataGrid_KnownEndpoints_MouseDoubleClick(object sender, System.Windows.Input.MouseButtonEventArgs e)
        {
            if (DataGrid_KnownEndpoints.SelectedItem == null)
            {
                return;
            }
            var selectedEndpoint = DataGrid_KnownEndpoints.SelectedItem as Endpoint;

            if (selectedEndpoint.Hostname == "Custom")
            {
                Textbox_Computer.Focus();
                return;
            }
            ConditionalRDPConnection(selectedEndpoint);
        }
        private void DataGrid_KnownEndpoints_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            string   hostName = string.Empty;
            Endpoint endpoint = (DataGrid_KnownEndpoints.SelectedItem as Endpoint);

            if (endpoint != null)
            {
                hostName = endpoint.Hostname.ToString();
                if (hostName == "Custom")
                {
                    Textbox_Computer.IsReadOnly = false;
                    hostName = string.Empty;
                    Textbox_Computer.Focus();
                }
                else
                {
                    Textbox_Computer.IsReadOnly = true;
                }
            }
            Textbox_Computer.Text = hostName;
        }