Hi, I've created a Flex 4 app that mimics the FlexJS Express example, DataBindingExample. You can look at the code here: https://paste.apache.org/I6cM
If you compare the MXML section in the Flex 4 example to the FlexJS Express example you will see they are nearly the same - at least in number of MXML elements. The Express package bundles up common beads, such as the data-binding beads, into Express components, making it simpler to write Flex applications. Note that the FlexJS DataBindingExample has model, view, and controller parts; this Flex 4 comparison is self-contained to a single file. Regards, Peter Ent Adobe Systems/Apache Flex Project