Code Bubbles Project is an interesting scientific project that tries "Rethinking the User Interface Paradigm of Integrated Development Environments". The core idea may seem controversal, but the video is definitely worth watching. We also have a discussion about this on our forum: Code bubbles - IDE przyszłości? [pl].
When it comes to my opinion, I'm enthusiastic about this - at least about half of this project. For very long time I dream about opening and editing single classes or function definitions instead of navigating over smaller or larger source files. I think that grouping such definitions into source code files as an intermediate step between whole project and single class or function is just unnecesary. Of course those who like to extensively use preprocessor macros, Find&Replace or grep would not agree, but I believe the future is in authomatic code refactoring like "Rename symbol" and intelligent code navigation like tracking call graph.
But on the other hand, I don't like the idea of having bubbles spread over 2D workspace that can panned and zoomed. It remains me of so called mind maps, which I truly hate. I always prefer to write down my ideas, knowledge, design and everyting as pure text in a tree-like nested lists, so for me, it would be more convenient in Code Bubbles to just have a tree of classes and methods and open them in separate tabs, floating windows or something like this.