Nesting of UI elements is a nice feature if you want to have a control within another control. For example, you can nest our combobox within a RibbonBar chunk. Not all Winforms suites offer this type of functionality, this is why we have listed it as a feature.
The usability of this feature is not immediately noticable, but it is there in case you need it. Since you mentioned RadTreeView
, it has properties which could be used in situations when you want to host items or controls in a tree node. I have attached a very simple project which demonstrates how to add a button to RadTreeNode.
Let me know if you have other questions.
the Telerik team