I've seen blue, green and yellow, but I have no idea what they mean.
I am talking about the little lightbulb looking icon in the top left corner indicating if the program is using in administrator or general users.
I saw green earlier today when my computer was being slow
That's an indication of whether that list is source, destination or other.
Here's the page in the manual that explains it:
Source and Destination
Take note of the last screenshot snippet on that page where it shows the Source lister with a yellow icon and a destination lister with a red icon.
Ahh.. I wondered about that. Should've known THanks!