An application sends the WM_MDIRESTORE message to a multiple document interface (MDI) client window to restore an MDI child window from maximized or minimized size.
WM_MDIRESTORE
wParam = (WPARAM) (HWND) hwndRes; // handle to child to restore
lParam = 0; // not used; must be zero
The return value is always zero.
Windows NT: Requires version 3.1 or later.
Windows: Requires Windows 95 or later.
Windows CE: Unsupported.
Header: Declared in winuser.h.
Multiple Document Interface Overview, Multiple Document Interface Messages, WM_MDIMAXIMIZE