I just found a "user created" bug, user created as in "me" (not Mike!)
If you install Advanced Config 3.3 and disable the dialer skin (to kill S2A and get the newly slick OEM dialer) the call volume control is gone. The visual slider portion works, just the actual volume doesn't change. Reenabling the skin (and S2A
) brings back the volume adjustment. I'd love to find a cure for this as I prefer both the OEM lock and dialer.