UIHierarchy is a library that facilitates creation of user interfaces. The main idea is to enforce the mental picture of the containment hierarchy of GUI components by writing the code in the same logical way. Code gets much easier to understand, much shorter, and easy to maintain. Additionaly, UIHierarchy can manipulate resulting components hierarchies in a powerful way.
[It is a UI helper library, but no category of this site really match. UIHierarchy has a small XML module though but it is not the main focus.]