private void AddButton_Click(object sender, RoutedEventArgs e)
        {
            var textDialog = new TextEditDialog("Create new Tag:", Tags);

            if (textDialog.ShowDialog() == true)
            {
                if (Tags == null)
                {
                    Tags = new List <string>();
                }
                Tags.Add(textDialog.Text);
                TagsListBox.Items.Add(textDialog.Text);
            }
        }
        private void EditButton_Click(object sender, RoutedEventArgs e)
        {
            if (_selectedTag == null)
            {
                return;
            }

            var textDialog = new TextEditDialog("Edit Tag:", Tags, _selectedTag);

            if (textDialog.ShowDialog() == true)
            {
                Tags.Remove(_selectedTag);
                TagsListBox.Items.Remove(_selectedTag);

                Tags.Add(textDialog.Text);
                TagsListBox.Items.Add(textDialog.Text);
            }
        }