Paraphrasing [myself][1]:

If you’re ok with changing things everywhere, the behavior of scroll bars can be changed in System Preferences. (Look in General or search for `scroll bar behavior.`)

Set it to “always” display and the issue will be fixed. Scroll bars will always be shown below the scrollable content, like so:

>![][2]


  [1]: https://meta.stackoverflow.com/a/326476/6083675
  [2]: https://i.sstatic.net/pzjj4.png