The progress bar usually shows light to dark blue here for chunks that
exist but that I didn't get yet. However, when I have a dead file, with
non-existing chunks thus, automatic 'no needed source dropping' causes
one to jump of happiness (in the beginning) often because: those chunks
turn from red to blue! The reason is that when you have a "source' in the
state "unknown", that is counted the same as 'existing' resulting in the blue
color.
