In C#, VS has a class view that lets you jump around by class name. You can split the window and compare within the same file just fine. And if anything, you're complaining about VS's lack of capabilities.

I'm not arguing that you never want a separate file, just that having a forced "one class per file" rule just sprays files all over and means you have to jump around more. Java's hierarchy+class=file is just silly; there's nothing stopping people from enforcing that themselves, if they so choose.