/// <summary>
/// Sort the tree view item source collection
/// </summary>
private void Sort()
{
List <DisplayableTreeViewItem> items = ItemSource.ToList <DisplayableTreeViewItem>();
items.Sort((x, y) => CompareItems(x, y));
ItemSource.Clear();
for (int i = 0; i < items.Count; i++)
{
ItemSource.Insert(i, Sort(items[i]));
}
}