FSX: G1000 panel, can't change NAV frequency

I just installed FSX and tried out the 172 with G1000 panel. I have
never used a G1000 panel, but I'm curious.

Strangely, if I click on the "NAV" button on the upper left corner of
the panel, I can only change the digits to the right of the decimal
point,
not the integer ****tion of the frequencies. So I can cycle through
a VOR frequency of 113.00 -> 113.95, but I can not change it
to 112.10.

I google'ed around and still can not find anything (not even from
Garmin's various guides online).

P S