Signum.Windows.AutocompleteTextBox.txtBox_LostFocus C# (CSharp) Метод

        private void txtBox_LostFocus(object sender, RoutedEventArgs e)
        {
            if (!pop.IsKeyboardFocusWithin)
            {
                if (string.IsNullOrEmpty(this.txtBox.Text))
                    SelectedItem = null;

                Close(CloseReason.LostFocus);
            }
        }