When you use introspection, the framework keeps all type info objects in memory until you close the application. This caching is for performance reason. See case 26079 in Feedback.
A year ago I created the case 35899 (Introspection: Ability to clear the cache).
I think it makes debugging difficult. One thing I try to do is to check the memory objects before quitting an application. If there is more than the App object and a few menu items, I have a problem somewhere. With thousands of introspection objects mixed in, this check is impossible. If one could at least hide the introspection objects temporarily in the debugger!
Thanks for the info. I agree though Eli, it would be great if we can clear or hide this information as it makes looking for memory issues much more difficult.