Page heading

Supposed browse-by-alphabet system:

(iriver only)
Enabled by clicking the joystick.
Disabled by clicking the joystick again

While enabled, the file selected is centered in the screen

Once enabled:
Up: Go to the previous letter of the alphabet
Down: Go to the next letter of the alphabet
Right: Lock the previously selected letter in place, and move the cursor to the next letter.
Left: Go to the previous letter, if/when possible