title: Use mouse scroll wheel in Vim
body: <p>My <code>.vimrc</code> has the following lines</p>
  
  <pre><code>set mouse=a
  map &lt;ScrollWheelUp&gt; &lt;C-Y&gt;
  map &lt;ScrollWheelDown&gt; &lt;C-E&gt;
  </code></pre>
  
  <p>But when I scroll up using the mouse wheel, I'd get the text <em>above</em> Vim. For example, I'd get my terminal session text if I'd just started Vim. I'm initially experimenting with the mouse scroll wheel on help files, then move on to other files, hence the <code>a</code> option.</p>
  
  <p>What else do I need to set? I'm using Snow Leopard and Vim 7.3 inside a Terminal.</p>
  
  <p>Here, I just did a wheel up. See the Terminal session at the top.
  <img src="https://i.stack.imgur.com/TVojW.png" alt="enter image description here"></p>