If it was an ActionScript project you would have to import the class and reference it somewhere in the project for the class to be compiled in -- which adds to swf file size.
In Flex, by referencing the event in a tag -- that is probably the reference to compile it in.
<Button click="myClicker()" />
Debugging undocumented components. Dont worry, I was not planning this for a live product. But it would be extremely useful to either A, lsiten for ALL events with 1 command such as _someObj.addEventListener("*", debugEventHandler); or as part of EventDispatcher().dispatchEvent(blarblar) have it trace/log out automatically, for EVERY EVENT.. EVER. Yes, an eventlog may get very big very fast, I would prob end up putting in a filter function such as EnterFrame but It would be great to just have the option for those bugs that are deep in either Flash's Own code (yes, they exist) or 3rd party components.