WM_MDIDESTROY

When sent to a multiple document interface (MDI) client window, this message causes a child window to be closed.

Parameters

wParam

Contains the window handle of the child window.

lParam

This parameter is not used.

Comments

This message removes the title of the child window from the frame window and deactivates the child window. An application should close all MDI child windows with this message.

If a client window receives any message that changes the activation of child windows and the currently active MDI child window is maximized, Windows restores the currently active child and maximizes the newly activated child.