title: How do I set a React ref to another element onMouseEnter?
body: <p>Given that I created a ref, I have a list of items.</p>
  
  <p>When I do <code>onMouseEnter</code> on an element, I want this ref to point to that element.</p>
  
  <p>How can I achieve this?</p>
  
  <p>I need this ref because I need to display a popup next the element, and CSS won't help since the elements are inside a <code>ul</code> and then a <code>container</code> with <code>overflow:hidden</code></p>