Regarding the interactive tutorial

[Jim Byrnes]

Is there a way to "rewind" it. That is back up a step or two. I managed 
to mess it up a couple of times and it would have been nice to redo a 
previous step instead of having to start over.

I'm curious if anyone else using Linux (Ubuntu in my case) had trouble 
figuring out how to scroll the icon picker.  It wasn't until I googled 
and saw a screen shot that I noticed the little handle you use.  Even 
after I knew what to look for I trouble seeing it.

Regards,  Jim