title: Is there a better way to (Un)select all LegendItems in HighCharts LineChart?
body: <p><a href="https://jsfiddle.net/9100bo/1mpwur8s/2/" rel="nofollow noreferrer">Here is my demo</a></p>
  <pre><code>const seriesAmount = 90;
  </code></pre>
  <p>When the variable 「seriesAmount」 is &lt; 50,</p>
  <p>everything works smoothly,</p>
  <p>but when it's &gt; 50,</p>
  <p>you have to wait such a long time to Unselect them.</p>
  <p>Is there a better solution to fix this problem?Thanks!</p>