Holy cow, I wrote a book!
Suppose you have a TreeView control, and you created an item in it,
and you want to move the HTREEITEM to a new parent.
How do you do that?
You can't, at least not all in one motion.
You will have to delete the HTREEITEM and then
re-create it in its new location.
If you want to move an HTREEITEM within the same parent
(say, to reorder it among its siblings),
then you can use
and pass a custom sort function that rearranges the children into
the order you want.