private void BackgroundColorPickerButton_Click(object sender, RoutedEventArgs e)
        {
            var command = new ReadColorCommand();

            Action <Color> action = c =>
            {
                presentation.Style.BackgroundColor = c;

                BackgroundColorPickerButton.Background = new SolidColorBrush(c);
                PreivewBackgroundColor.Background      = new SolidColorBrush(c);
            };

            command.Execute(action);
        }
        private void AnswerColorPickerButton_Click(object sender, RoutedEventArgs e)
        {
            var command = new ReadColorCommand();

            Action <Color> action = c =>
            {
                presentation.Style.AnswerHighLightColor = c;

                AnswerColorPickerButton.Background = new SolidColorBrush(c);
                ChoiceBorder.BorderBrush           = new SolidColorBrush(c);
            };

            command.Execute(action);
        }