var
    WindowPlacement: TWindowPlacement;
{hWin is the handle of the Window}
begin
    WindowPlacement.length := SizeOf(WindowPlacement);
    if GetWindowPlacement(hWin,@WindowPlacement) then begin
        case WindowPlacement.showCmd of
            SW_HIDE:
                ShowWindow(hWin,SW_SHOW);
            SW_SHOWMAXIMIZED: ;
        else
            ShowWindow(hWin,SW_RESTORE);
        end;
    end;
end;