Thanks. I think the Interface has changed from the videos I've been watching.
I finally figured that when you click on the UI icon and choose to edit a Select, there is now a toggle on Text Editor. If you're on the "Text editor" side, you have massive trees you can edit individually, as you pointed out--but not the overall expression. If you want to change the whole CSS completely, you toggle to the other side and replace the entire expression.
Note: if you come back, you can't toggle to Text Editor without losing the CSS you put in. The interface is NOT intuitive--It took me several days to figure out.
