I only just opened up 2.2, so I'm sure there are other treats in store, but when I read "part outlines" on new features description it didn't mean much to me - just thought it was a wireframe view of some sort. Well I suppose it is, but super useful, as gives preview of object and its location in the part tree as you click on the name without having to show and hide the part.
A little feature, but very useful, nice thinking on the UI. Thanks for that.
Stephen