JSFL - reading metadata onDocumentChanged

Question

I am building a flash panel that reads metadata from a .fla when it is active in the Flash IDE. This panel is also storing metadata in the .fla and that is no problem. What is problematic is that I do not know how to stop the event listener from listening for onDocumentChange.

I want it to listen for it as long as it is open, but when it's closed it should clean up after itself because trying to read metadata every time a new document is selected is not a very nice thing to do.

I have tried to listen for all kind of events in the panel to detect when the user closes it, but with no success.

Anyone knows anything about this?