Layout class and garbage collection

I’ve been running into some serious memory issues that I’m trying to track down at the moment. For some reason my dynamic swfs that I’m loading never get garbage collected so I’m assuming there is a reference to them somewhere.

I use senocular’s layout class so I was wondering if anyone knew steps you need to take to cleanup any objects used in that. For instance when I register a new layout and pass a reference to the display object to be tracked, does that interfere with garbage collection or is it a weak reference?