This is something I want to do quite often, as I end up with hundreds of source files visible in Solution Explorer and things can get quite confusing.
I have found several extensions which will do this in Visual Studio, but as Visual Web Developer 2010 Express doesn't support extensions I'm looking for an alternative solution.
Any suggestions gratefully received!
Edit: In case it wasn't clear from the question title, I want to collapse folders recursively, not just hide the expanded sub-tree and have it show in the same state when I open the parent folder again.
Ok, after five months I'm assuming there just isn't a way to do this. Marking as answered.