title: Eclipse Luna: Indentation size for xml is not editable
body: <p><a href="https://i.stack.imgur.com/l0a9N.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/l0a9N.jpg" alt="enter image description here"></a></p>
  
  <p>I am trying to edit the indentation size for xml in Eclipse Luna on Ubuntu 12.04
  I am not able to edit it. 
  I remember being able to edit it on a different version of Linux/Ubuntu.</p>
  
  <p>Is there a reason why this is not editable?</p>
  
  <p>Please let me know if posting any other information would be helpful to troubleshoot this.</p>
  
  <p>Thanks Awesome people.</p>