title: Show Text on Clicking Two Points on Highcharts?
body: <p>Given an existing Highcharts (in a React component using <code>highcharts-react-official</code>), how can we make it such that when the user clicks on 2 points on the chart, the difference in values between these 2 points will be calculated and shown on the chart in a text box?</p>
  <p>To illustrate the desired result, below is an image that shows a green text box with the percentage difference in values after the user clicks on 2 points on the line chart.</p>
  <p>How can we achieve this using Highcharts?</p>
  <p><a href="https://i.stack.imgur.com/41lQX.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/41lQX.png" alt="enter image description here" /></a></p>