rollback #3358

closes #3391

For users who need to hide the scrollbars while zooming text in the meantime, you can add the following to your custom.css:

```css
.CodeMirror-scroll, .CodeMirror-wrap .CodeMirror-scroll {
 overflow: scroll;
}

.CodeMirror-vscrollbar, .CodeMirror-scrollbar-filler, .CodeMirror-hscrollbar {
   visibility: hidden;
}
```