title: how do you get each item in a scatterchart legend to appear only once
body: <p>The legend in my scatter chart shows a cluster for every point, I would like it to just show the unique items, and therefore it should only have 3 (A, B, C) not 6.</p>
  
  <p><img src="https://i.stack.imgur.com/W6ibh.png" alt="enter image description here"></p>