It would be cool/useful if I could color-code my notebooks, to see which notebook window I have open. For instance, we could make the windows/frames or notebook list a certain color, depending on which notebook it is.
On my mac, I switch back and forth between a lot of notebook windows and sometimes get confused which notebook I save my notes. Also, when you have a lot of notebooks for different workspaces, its sometimes hard to search for the right notebook.