I need to shrink a partition so I used Defraggler from a ubcd4win disk to do an free space defragmentation. After completing the analysis looks like this:
Click to view attachment
What is it trying to tell me by those light blue boxes? The mouse tool tip says they don't contain files, but shouldn't they be white then?

EDIT: Okay, the online doc gives an official definition for light blue so the topic is wrong, but I still don't get why he says there are no files but it's still blue...