title: Codeigniter: user defined helper function does not load
body: <p>I made a custom helper extending the system string_helper.php.</p>
  
  <p>I placed it in my <code>/application/helpers</code> directory, called it <code>MY_string_helper.php</code> as required, unit-tested its functions.</p>
  
  <p>Now, when I try to call one of its functions from a model, it does not work.</p>
  
  <p>The functions in the default string helper work, instead. It looks like my extension is not loaded for some reasons.</p>
  
  <p>Thanks a lot, and happy holidays.</p>
  
  <hr>
  
  <p>Edit: even funnier. I saved the file as <code>categories_helper.php</code> in the <code>system/helpers</code> directory, and when I try to load it within a model i got the following response: *Unable to load the requested file: helpers/categories_helper.php*</p>