// CMainFrame::OnRestoreWindow() is a menu command handler for
// CMainFrame class, which in turn is a CMDIFrameWnd-derived class.
// It restores the current active MDI child window from maximized 
// or minimized size.
void CMainFrame::OnRestoreWindow() 
{
   BOOL maximized;
   CMDIChildWnd* child = MDIGetActive(&maximized);
   if (child && (maximized || child->IsIconic()))
     child->MDIRestore();     // or MDIRestore(child);
}