There is a difference between supported games and games that provide additional LCD display information.
Logitech Game Panel software supports games by offering preconfigured G-keys macros. Supported games are also auto detected by the G15 keyboard.
To use the LCD display, your game must also include support for this feature. LCD display support is up to the game manufacturer and not all games provide this. Examples of games which do support the LCD display include World of Warcraft and Crysis: Warhead.
Some games and applications may require the user to manually enable G-Series LCD support. Please check within the game application settings window or contact the game manufacturer for additional assistance.