/// <summary>
        /// Provides an ability to rename a tree view item
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private static void RenameMenuOption(object sender, RoutedEventArgs e)
        {
            var parent = TreeView.SelectedItem as TreeViewItem;

            if (parent != null)
            {
                var renameWindow = new HelperWindows.RenameWindow();
                renameWindow.ShowDialog();

                if (renameWindow.DialogResult == true)
                {
                    var treeItemToRename =_subscriptions.Search(parent.Header.ToString());

                    if (treeItemToRename != null)
                    {
                        treeItemToRename.Name = renameWindow.newName;
                        parent.Header = renameWindow.newName;
                    } 
                }
            }
        }
        /// <summary>
        /// renames a topic
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void RenameTopicMenuOption(object sender, RoutedEventArgs e)
        {
            var parent = topicTreeView.SelectedItem as TreeViewItem;

            if (parent != null)
            {
                var renameWindow = new HelperWindows.RenameWindow();
                renameWindow.ShowDialog();

                if (renameWindow.DialogResult == true)
                {
                    parent.Header = renameWindow.newName;
                }
            }
        }