title: Display issue with oh-my-zsh agnoster theme
body: <p>I've added the theme in the zshrc file like so:</p>
  
  <pre><code>ZSH_THEME="agnoster"
  </code></pre>
  
  <p>But it ends up looking like this:</p>
  
  <p><a href="https://i.stack.imgur.com/Cxo6b.png" rel="noreferrer"><img src="https://i.stack.imgur.com/Cxo6b.png" alt="enter image description here"></a></p>
  
  <p>I'm on Ubuntu Gnome 16.04. What am I missing?</p>