Can someone explain to me the difference between the arrow on the progress bar and the dark grey portion of the progress bar? For example this is the book I am reading now:
http://cl.ly/3U1L0c2v2b081z233V38
If there was either just an arrow or just a grey bar, I would assume that it represents where I am in the book. But they are at different positions, so I'm at a complete loss as to which one represents where I am, and what the heck the other one represents at all.
Thanks!