title: Can't insert into Editable
body: <p>I must be doing something obvious, but I can't figure out what it is. I'm simply trying to insert a character into an Editable:</p>
  
  <pre><code>@Override
  public void afterTextChanged(Editable s) {
      Log.d(TAG, "inserting space at " + location);
      s.insert(location, " ");
      Log.d(TAG, "new word: '" + s + "'");
  }
  </code></pre>
  
  <p>But s never changes. The string 's' is long enough, because I print it and it looks good. If I call Editable.clear(), it is cleared, and I can replace multiple characters with Editable.replace(). Ideas?</p>