I defragged my drive, all nice and blue and stacked together, it was completed at 100%. Then, just for curiosity I tried with clicking on defrag again hoping it would just be instant 100% and surprisingly it started to defrag, moving out blue files, making red and, to sum up, defragging again.
Might this be a bug? Did defraggler found a new order the second time better than the first time? However that drive wasnt almost modified at all, its the storage drive which I would say not even the 0.5% of it was modified by me or other programs in the time the first defrag lasted.
Im tempted to try to press the button a third time, but it takes a couple of hours...