/// <summary>
        /// Method to insert number on cell focus
        /// </summary>
        /// <param name="sender">The object that initiated the event.</param>
        /// <param name="e">The event arguments for the event.</param>
        private void InsertNumber(object sender, RoutedEventArgs e)
        {
            if (CheckBoxEnableNumber.IsChecked == true)
            {
                TextBox currentCell    = sender as TextBox;
                string  selectedNumber = this.FindSelectedNumber();

                if (!currentCell.Name.Contains("Note"))
                {
                    currentCell.Text = selectedNumber;
                }
                else
                {
                    string  cellname     = currentCell.Name;
                    string  x            = cellname.Substring(8, 1);
                    string  y            = cellname.Substring(9, 1);
                    string  gamecellName = "Cell" + x + y;
                    TextBox gameCell     = FindName(gamecellName) as TextBox;

                    if (string.IsNullOrWhiteSpace(gameCell.Text))
                    {
                        List <string> tags        = new List <string>();
                        string        currentTags = currentCell.Text;
                        foreach (char c in currentTags)
                        {
                            tags.Add(c.ToString());
                        }

                        if (!tags.Contains(selectedNumber))
                        {
                            tags.Add(selectedNumber);
                        }

                        List <string> sortedTags = tags.OrderBy(c => c).ToList();
                        currentCell.Text = string.Empty;
                        foreach (var tag in sortedTags)
                        {
                            currentCell.Text += tag;
                        }

                        NoteGrid.Focus();
                    }
                }
            }
        }