ubuntu 12.04 vnc keymap has trouble, D become minimize all windows and S become start menu, run these to fix it.

DISPLAY=:1 xmodmap -e 'keysym Alt_L = Alt_L'
DISPLAY=:1  xmodmap -e 'keysym Alt_R = Alt_R'
DISPLAY=:1 xmodmap -e 'keycode 255 = Meta_L'
DISPLAY=:1  xmodmap -e 'keycode 254 = Meta_R'
DISPLAY=:1  xmodmap -e 'keycode 253 = Super_L'
DISPLAY=:1  xmodmap -e 'keycode 252 = Super_R'
DISPLAY=:1  xmodmap -e 'add mod3 = Super_L Super_R'
DISPLAY=:1  xmodmap -e 'add mod4 = Meta_L Meta_R'