WM_ENTERIDLE    
The
WM_ENTERIDLE message is sent to the owner window of a modal dialog box or menu
that is entering an idle state. A modal dialog box or menu enters an idle state
when no messages are waiting in its queue after it has processed one or more
previous messages. 
WM_ENTERIDLE 
fuSource = wParam;   
// idle-source flag 
hwnd = (HWND) lParam; // handle of dialog box or
owner window 
 
Parameters
fuSource
Value of wParam.
Specifies whether the message is the result of a dialog box or a menu being
displayed. This parameter can be one of the following values: 
| Value | Meaning | 
| MSGF_DIALOGBOX | The system
  is idle because a dialog box is displayed. | 
| MSGF_MENU | The system
  is idle because a menu is displayed. | 
hwnd
Value of lParam.
Contains the handle of the dialog box (if fuSource is MSGF_DIALOGBOX) or
of the window containing the displayed menu (if fuSource is MSGF_MENU). 
Return Values
An
application should return zero if it processes this message. 
Remarks
The DefWindowProc
function returns zero. 
See Also