Google Prettify: Line numbers won't show

Question

For some reason, my line numbers won't show. Is this a known issue? Code coloring works fine. It's just the line numbers that won't show

HTML

<pre class="prettyprint linenums"><code class="language-html">
    &lt;h1 class="test"&gt;This is a header&lt;/h1&gt;
    &lt;p&gt;This is a paragraph&lt;/p&gt;
</code></pre>

Does anyone know what can cause this?

Answer 1

Found the issue. It had to do with setting list item to display:inline-block. Removing that fixed it.