title: ace editor cursor behaves incorrectly
body: <p>I am using Ace editor in my project.</p>
  
  <p>CSS: </p>
  
  <pre><code>#editor {
    position:absolute;
    top:0;
    left:0;
    width:100%;
    height:100%;
    background-color:white;
  }
  </code></pre>
  
  <p>JavaScript: </p>
  
  <pre><code>var editor = ace.edit("editor");
  editor.setTheme("ace/theme/textmate");
  editor.getSession().setMode("ace/mode/java");
  </code></pre>
  
  <p><code>#editor</code> is contained in a relatively positioned div.</p>
  
  <p>The problem is hard to explain but I'll try.</p>
  
  <p>Whenever I type text in Ace as the line size increases the spaces in the cursor's actual position and it's expected position increases.</p>
  
  <p>For example when I type "This is text" it shows like this:</p>
  
  <pre><code>This is text           |
  </code></pre>
  
  <p>Now when I press backspace key it will delete last character on line 't', and will show: </p>
  
  <pre><code>This is tex           |
  </code></pre>
  
  <p>I have searched about this issue on Google found one similar issue for chrome browser when zoom is set to 120.
  but I'm working on Firefox browser.</p>