Hi, I tested following code. ---------------------------- cfg = {"a" => 1, "b" => 2} $= = true p cfg['a'] cfg['a'] = 10 p cfg p cfg['a'] $= = false cfg['a'] = 20 p cfg the result is ------------------- nil {"a"=>1, "a"=>10, "b"=>2} 10 {"a"=>20, "a"=>10, "b"=>2} -------------------------- Is this BUG or feature?