Ryan Small has posted a nice tip article to his "The Autodesk Informer" blog. The tip is on how you can use the Object Propties Manager to access a list of nested objects in a selection set. A quick example would be to select a bunch of objects of various types in your drawing. With the items selected you can essentially sort and sub select based on entity type like all circles, lines or hatches. This is a quick way to change all circles in a selection set to a same diameter.
Link to the tip: Click Here
Cheers,
-Shaan
