title: highcharts tooltip shows scroll bar
body: <p>My highcharts chart tooltip shows an blank scrollbar. This also applies to highstock chart. This issue only occurs on firefox.</p>
  
  <p>I have applied this style in my css file. But it works fine in chrome.</p>
  
  <pre><code>.highcharts-tooltip span {
  max-height:250px !important;
  overflow-y: scroll !important;
   }
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/NEvYM.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/NEvYM.png" alt="enter image description here"></a>
  How can I solve this?</p>