在第一个模态中打开另一个模态时，启动模态问题

我有一个打开并显示信息的模态。在模态中，有一个注册按钮。单击该按钮后，将关闭第一个模态并打开一个新的"注册"模态。当我关闭该模态时，问题出现了，模态消失了，但背景仍然不透明，我无法访问它背后的页面。这是我的代码。我希望模态在点击任何按钮或关闭模态本身作为默认行为时完全关闭。

<div class="modal fade" id="register-for-fame" tabindex="-1" role="dialog" aria-labelledby="registerForFame">
        <div class="modal-dialog" role="document">
            <div class="modal-content">
                <div class="modal-header">
                    <button type="button" class="close" data-dismiss="modal" aria-label="Close">
                        <span aria-hidden="true">&times;</span>
                    </button>
                    <h4 class="modal-title" id="registerForFame">Register For Fame</h4>
                </div>
                <div class="modal-body">
                    <p>
                        Some text
                    </p>
                    <p>
                        more text
                    </p>
                </div>
                <div class="modal-footer">
                  <button type="button" class="btn btn-primary flow-left" data-dismiss="modal">
                    Not right now
        </button>
                    <button type="button" class="btn btn-primary register-user" data-dismiss="modal">
          <a href="#" data-toggle="modal" data-target=".register-user">want to register!</a>
                    </button>
                </div>
            </div>
        </div>
    </div>
<div class="modal fade register-user" tabindex="-1" role="dialog" aria-labelledby="mySmallModalLabel">
  <div class="modal-dialog modal-sm">
    <div class="modal-content padding-sides">
      <h3 class="center">Register!</h3>
      </br>
      <input type="text" class="form-control" id="user-name" size="30" placeholder="Username:">
      </br>
      <input type="text" class="form-control" id="password" size="30" placeholder="Password:">
      </br>
      <input type="text" class="form-control" id="confirmation-password" size="30" placeholder="Confirm Password:">
      </br>
      <input type="text" class="form-control" id="email-address" size="30" placeholder="Email (optional):">
      </br>
      <p>some text</p>
      <button type="button" class="btn btn-primary flow-left" data-dismiss="modal" data-toggle="modal">
        Not right now
      </button>
      <button type="button" class="btn btn-primary submit-registration flow-right" data-dismiss="modal" data-toggle="modal">
        Register me!
      </button>
    </div>
  </div>
</div>