Every time the function is invoked, `Ghost.Editor.HTMLPreview.scrollViewPort()` it returns `$('.entry-preview-content')` which itself is a function invocation, and subsequently a read to the DOM.  

Updating it to

```
if (!$entryPreviewContent) {
  $entryPreviewContent  = $('.entry-preview-content');
}
return $entryPreviewContent;
```

Will prevent that jQuery invocation.