What is Rio? Rio is a framework written in AS3, targeted for developing rapid and stable gui components. It is light weight, has a minimal memory footprint and written without any dependecy of a external library, so it works great in any flash publishing platform, such as Flash/Flex-builder, FDT, FlashDevelop and the Flash EDI.
The framework itself has a few off the shelf ready components but the main goal with the framework is to extend the abstract classes and make you own components.
Please not that this library is here for historical purposes, it is no longer maintained