title: How can I set a "hidden" attribute for text inside NSAttributedString?
body: <p>I have a Cocoa app with an <code>NSTextView</code> control which holds its text in an <code>NSAttributedString</code> (actually I believe it's a <code>NSMutableAttributedString</code>). I can easily set and modify different text attributes (such as font, underline, etc.) on different character ranges inside that string.</p>
  
  <p>However, I want to set a part of the text as <strong>hidden</strong> (similar to the effect of the CSS attribute <code>display: none</code>). When an external event occurs (say a button clicked), I want to unhide or hide that specific range of characters.</p>
  
  <p>Is there anyway to do this with <code>NSAttributedString</code>?</p>