The BN_DISABLE notification message is sent when a button is disabled. The parent window of the button receives this notification message through the WM_COMMAND message.
BN_DISABLE
Note This notification message is provided for compatibility with applications written for 16-bit versions of Windows earlier than version 3.0. Win32-based applications should use the BS_OWNERDRAW button style and the DRAWITEMSTRUCT structure for this task.
Windows NT: Requires version 3.1 or later.
Windows: Requires Windows 95 or later.
Windows CE: Unsupported.
Header: Declared in winuser.h.
Buttons Overview, Button Messages, DRAWITEMSTRUCT, WM_COMMAND, WM_DRAWITEM