private void SelectedQuestionPositionDownExecute()
        {
            if (QuestionVMs.Count <= 1 || QuestionVMs.IndexOf(SelectedQuestion) == QuestionVMs.Count - 1)
            {
                return;
            }

            var selectedIndex = QuestionVMs.IndexOf(SelectedQuestion);

            QuestionVMs.Move(selectedIndex, selectedIndex + 1);
            _recalculateNumbers();
        }