title: Sitecore: "You cannot drag an item onto itself" error when clicking on an item in IE
body: <p>After updating a Sitecore instance from 6.3 to 6.6, we get the following error message when clicking on an item in the content editor:</p>
  
  <p><a href="https://i.stack.imgur.com/Lls0x.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Lls0x.png" alt="enter image description here"></a></p>
  
  <p>This only happens with the Internet Explorer. What could be the cause for this?</p>