Thanks for the sneak-peek, that's pretty awesome!

Well I don't want to be stubborn regarding the layers thing :p It's just a personal opinion that it's a better paradigm that it's widely used. Also I explained above why there are no side effects from showing/hiding an object. It can reside in it's own layer and together with other objects have it nested in a higher in hierarchy layer. Thus you could hide/unhide it without affecting other objects.
Anyways, the new thing you've been working on seems like it adds some great functionality!

Here's a screenshot of the thing I've been working on. Ignore the gazillion buttons in the browser pane, they were there for development :p