Sent to a window immediately before it loses the keyboard focus.
A handle to the window that receives the keyboard focus. This parameter can be NULL.
This parameter is not used.
An application should return zero if it processes this message.
If an application is displaying a caret, the caret should be destroyed at this point.
While processing this message, do not make any function calls that display or activate a window. This causes the thread to yield control and can cause the application to stop responding to messages. For more information, see Message Deadlocks.
Minimum supported client
|Windows 2000 Professional [desktop apps only]|
Minimum supported server
|Windows 2000 Server [desktop apps only]|