Hey guys/Pokey! Sorry for joining the party so late, but I've been behind on my podcasts lately.
I'll get down to the subject, and that can be resumed in one acronim: R(F)TM. Rockbox is a complex piece of software and a lot of its functionality isn't obvious.
For instance, to lock the keys on the clip you need to press both the middle button (select) and home at the same time, while you are playing a song (rockbox devs name that the WPS - while playing screen). Also, if you are somewhere in the menus and you want to return to the wps you use the same key combo - home + select.
Also, at least on my Sansa e200, you can have it charge from a computer without accessing the disk by holding select while you plug in the usb cable. I don't know if it's the same for the Clip Plus.
As a closing note, if I recall correctly, the Clip Plus is still under development, especially the usb side of things, so you can expect improvements with each new release (unless you're using the current build, like I do).

Here's hoping you have a nice day,
Fragilematter