When Sorted is set to true, the TreeNode objects are sorted in alphabetical order by their Text property values. You should always use BeginUpdate and EndUpdate to maintain performance when you add a large quantity of items to a sorted TreeView. When the text of an existing node is changed, you must call Sort to resort the items.
The default sorter uses the Compare method based on the CurrentCulture specified by the application. This means that TreeNode objects with equal value are kept in the order in which they were added to the TreeView control.