显示语义ui模态时防止隐藏正文滚动条

Question

我正在使用语义UI框架来显示模式。 问题在于，当单击按钮显示模式时，首先隐藏主体滚动条，然后显示模式，而当关闭模式时，主体滚动条显示，页面向左移动。 现在我需要防止显示模式时隐藏正文滚动条。请帮忙 。 tnx

<div class="ui modal">
  <i class="close icon"></i>
  <div class="header">
    Profile Picture
  </div>
  <div class="image content">
    <div class="ui medium image">
      <img src="/images/avatar/large/chris.jpg">
    </div>
    <div class="description">
      <div class="ui header">We've auto-chosen a profile image for you.</div>
      <p>We've grabbed the following image from the <a href="https://www.gravatar.com" target="_blank">gravatar</a> image associated with your registered e-mail address.</p>
      <p>Is it okay to use this photo?</p>
    </div>
  </div>
  <div class="actions">
    <div class="ui black deny button">
      Nope
    </div>
    <div class="ui positive right labeled icon button">
      Yep, that's me
      <i class="checkmark icon"></i>
    </div>
  </div>
</div>

jquery语句是

$( ".nh-compare-page-title-sec" ).on( "click", function(){
      $('.ui.modal').modal('show');
});