private async void Delete_Click(object sender, RoutedEventArgs e)
        {
            string name = FilterListBox.SelectedItem as string;

            if (name == null)
            {
                return;               // No selection.
            }
            if (await this.ShowQuestionAsync("Are you sure you want to delete this item filter?") == MessageBoxResult.No)
            {
                return;
            }

            try
            {
                FilterManager.Delete(name);

                FilterNames.Remove(name);
            }
            catch (Exception ex)
            {
                // Check whether deletion of filter definition failed, or only game filter file.
                if (!FilterManager.Exists(name))
                {
                    FilterNames.Remove(name);
                }

                await this.ShowErrorAsync("An error occurred while attempting to delete item filter.", ex.Message);
            }
        }