I have never seen any use for knowing the folder size on the hard disk, perhaps somebody could explain why they need to know it.
What I require, and I don't think x2 can display, is the space a folder or folders will occupy on a CD or Zip drive (Nikos will no doubt correct me if I'm wrong). This requires the ability to calculate the occupied space based on different cluster sizes and I know of (and use) another file manager that does it.
you can get an approximate idea using the property page F12 of the selection which shows size on disk but without taking cluster differences into account
its just a 'thing' i think - habit too ....like your'e in a folder & just look down to see the total size of the folder....
i guess when your'e you are used to it doing anything more to see the size becomes a strain..
human mind.....& emotions at work :P