This is some text that we're using as a demonstration. You can see that the highlighting scrolls with the text. Here is an overlap. And here is some more text to fill out the div and make sure that the scroll bars appear. It just needs to be long enough to overflow the div. That should do it.

This is some text that we're using as a demonstration. You can see that the highlighting scrolls with the text. Here is an overlap. And here is some more text to fill out the div and make sure that the scroll bars appear. It just needs to be long enough to overflow the div. That should do it.