Please describe how this feature is done in Rockbox. How many buttons does it take to do this in Rockbox?

The way it is done in rockbox is here, although I still would have done it differently. This is just another way.

http://rockbox.haxx.se/mail/archive/rockbox-archive-2003-07/0068.shtml

I will think of a better way, and then I will describe it here.

-eric