IanG has all of the details here about a new button style for Win32 developers available in Vista, called the "command link."

And I thought I had gotten the memo that Win32 was dead.

#define BS_COMMANDLINK 0x0000000EL

and

#define BCM_SETNOTE (BCM_FIRST + 0x0009)

#define Button_SetNote(hwnd, psz) \

(BOOL)SNDMSG((hwnd), BCM_SETNOTE, 0, (LPARAM)(psz))

are key to using the new button style.

The bad part will be if it's only available for Vista and not XP or 2003 ...