Stated clearly in the Flash MX 2004 Documentation, it should be possible to place the cursor inside of any statement containing curly braces {} and then to press (Control + ‘) to select/highlight all the code contained within those curly braces.
However on Windows machines this doesnt appear to work, that is because the keyboard shortcuts have been mapped wrong, it does work but you have to use (Control + ~). This editing feature works fine on a Macintosh (Command + ‘). So either the documentation needs updating or the keyboard shortcuts need re-mapping. It’s very useful all the same especially when it comes to three for loops inside a function etc….