OpenPandora Main OS

Imagine this tab content:
Nubs, Pandora Input, PNDstore.

CURRENT BEHAVIOR:

Pressing "P" and "N" is succession jumps to "Nubs" eventually, as it first jumps to the first "P" item ("Pandora Input"), then to the first "N" item, "Nubs".

DESIRED BEHAVIOR:

That it acts like in most Linux file browsers or the Mac OS X Finder.

In detail: Pressing "P" and "N" within a certain time limit should combine them to the string "PN" and jump to the first item which starts with that string, i.e. "PNDStore". If no item matches, reduce the combination string by one character, try to match again, if that doesn't match, try matching again with one character less, ... , until only one character is left, and if that one doesn't match jump to the nearest previous lexicographical character, which matches.