Due to design decisions that were made 6-7 years ago from now, I will never implement it this way smile (as shown in your collage). Also, it's not handy to use and gets slower as more systems are supported, even if that would be added on demand. And last but not least it couldn't be implemented for all 4 "views", so it's actually not feasible.

With "classified by source file" you probably just mean to add a driver column to the game/machine lists that you can use to sort (or "filter" in the future). That's already planned. Adding another "view" that classifies the sets by the driver source is a major task, though.

A mind is like a parachute. It doesn't work unless it's open. [Frank Zappa]