title: Transparency issue in vim
body: <p>Whenever I source my <code>.vimrc</code> file, the the transparent background ends at the last line, or until I create new lines within the current buffer, instead of making the entire window background transparent.  In other words half of my window is transparent and the other half is dark.  </p>
  
  <p>The <code>set transparency=10</code> option is currently enabled in my <code>.gvimrc</code> file at the moment.  Just out of curiosity, why does macvim respond this way?  Is there a fix for this, other than just putting that option in my <code>.vimrc</code> file?</p>