title: Black part of page during capture with CasperJS
body: <p>I have a strange problem. I have to take screenshots from vk.com in album with comments.</p>
  
  <p>In this case everything is ok:</p>
  
  <p><img src="https://i.stack.imgur.com/yb4ER.jpg" alt="enter image description here"></p>
  
  <p>But when i click to load more comments, the screenshot has a black lower part:</p>
  
  <p><img src="https://i.stack.imgur.com/oEPyW.jpg" alt="enter image description here"></p>
  
  <p>The code is pretty simple:</p>
  
  <pre><code>// click on image
  casper.waitForSelector(".photo_row_img", function() {
      this.click('.photo_row_img');   
  });
  
  // get more comments
  casper.waitForSelector("#pv_comments_header", function() {
      casper.click('#pv_comments_header');    
  });
  
  // take screenshot
  casper.wait(10000, function() {     
      casper.captureSelector('capture.jpg', '#pv_photo_wrap'); 
  });
  </code></pre>
  
  <p>I spent two days and still do not understand what's going on.</p>