The sortChildren() method of the TreeView class will sort the child items of a tree-view item. But, it is always in ascending alphabetical order.
The underlying tree-view control provides a function that allows a custom comparison callback function to do custom sorting. This is similar to the same functionality in the list-view control.
It would be good to add this functionality to the TreeView control so the Rexx programmer could implement the comparsion function in a Rexx method.