title: why visibility is always setted to visible although in CSS is hidden?
body: <p>I am using ShadowBox for showing media. It has some property <strong>showOverlay</strong>, which i setted to false, because dont need it.
  Problem is that background is not accesible as if ShadowBox is  modal dialog although Visibility in CSS is setted as <strong>hidden</strong>. 
  In Chrome and Mozilla it will be changed to <strong>visible</strong> and is modal. It works manually if me changing it back again to <strong>hidden</strong>.</p>
  
  <p>BUT WHY it is always setted to <strong>visible</strong> in Chrome and Mozilla browsers sourcepage/css????</p>
  
  <p>Here are my <strong>CSS of ShadowBox</strong>:</p>
  
  <pre><code>#sb-container {
      position: fixed;
      margin: 0;
      padding: 0;
      top: 0;
      left: 0;
      z-index: 999;
      text-align: left;
      visibility: hidden;
      display: block;
  }
  
  #sb-overlay {
      position: relative;
      height: 100%;
      width: 100%;
      visibility:hidden;
  }
  
  #sb-wrapper {
      position: absolute;
      visibility: hidden;
      width: 100px;
  }
  </code></pre>
  
  <p>and it is what <strong>Chrome and Mozilla does</strong>! in Explorer it works!
  <img src="https://i.stack.imgur.com/Bua0z.png" alt="**enter image description here**"></p>