Why are there now 4 shades of gray?

[Laura Shoe]

I don't know if a new shade of gray has been slipped in, or I have just never noticed, but in grid view I am used to very light gray = active and selected, light gray = selected only, and darker gray = unselected. Now there is a very dark gray... what does it mean? (I know it isn't file type -- it happens on all file types.
[img width=6'' height=255]http://laurashoe.com/grid_gray_shades.JPG[/img]

Thanks!

 

[Laura Shoe]

Ok, I get it - it signifies members of a stack.

 

[Brad Snyder]

Nice one Laura, I've never noticed that. I don't use stacks regularly.

 

[Braders]

It's the same for the colors too.

 

[Winston]

It's always been that way, Laura.