The BN_HILITE notification message is sent when the user selects a button. The parent window of the button receives this notification message through the WM_COMMAND message.
BN_HILITE
This notification message is provided for compatibility with applications written for versions of Windows earlier than version 3.0. New applications should use the BS_OWNERDRAW button style and the DRAWITEMSTRUCT structure for this task.
BN_HILITE is the same as the BN_PUSHED notification message.
BN_PUSHED, BN_UNHILITE, DRAWITEMSTRUCT, WM_COMMAND, WM_DRAWITEM