The idea is a new control called Tree View. The existing controls (different galleries, drop down lists) make it very difficult (orimpossible) to work with hierarchical data structures. What we would like to have is a cascading tree view. You should be able to:
open and close cascading branches of the view
filter based on search term
select a node (or, if possible, sometimes multiple nodes)
I know that standard list view works to some extend here, but our hierarchy has 9000 items. It is very hard to select an item and somehow know that there are child items when using the existing controls.