One of the things that makes me laugh (and cry) about the Flex 2 documentation is that it implicitly assumes that the reader is familiar with Flash. Given that Flex is supposed to be a development environment targeted at traditional developers (familiar with Eclipse and source code control and the like), you'd think that it would be a fair assumption that at least a significant share of the readers of the Flex 2 doc set would be Java, C++ or C# programmers (like me) who are keen to understand how to build rich clients in Flex.
I guess that other newcomers to Flash will probably have the same frustrating time as I did trying to figure out how (and when) the AVM2 dispatches mouse, focus and keyboard events, how to refer to the instance's properties of a symbol created with Flash CS3 using the Flex Component Kit for Flash CS3, and how to write programmatic skins etc...
So I thought a guide to Flash for Flex programmers was needed and I even though about writing one. That is until I read Colin Moock's recently published Essential AS3 book. Section 2 is the essential "missing manual" on the AVM for Flex developers who don't come from a Flash background and Chapter 29 is the perfect introduction to the Flash IDE for Flex programmers.
One day there might be a book on the Flex class library of the same thoroughness and quality.