UserAgent: Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.87 Safari/537.36

Steps to reproduce the problem:
1. Open this JS Fiddle: https://jsfiddle.net/orxp7h3q/
2. Try drag any item in the list over another item
3. Aw, snap!

What is the expected behavior?
The page should not crash, the background color of the over item being yellow.

Try comment out `top: -9999em` in CSS and re-run, everything is good.

What went wrong?
I don't know.

Crashed report ID: 4ff777b800000000

How much crashed? Just one tab

Is it a problem with a plugin? N/A 

Did this work before? N/A 

Chrome version: 49.0.2623.87  Channel: stable
OS Version: 6.3
Flash Version: Shockwave Flash 21.0 r0

The `top: -9999em` is for accessibility.

I ever tried change `em` to `px`. It works for the short text. However, for long text, it does not works. Try this: https://jsfiddle.net/orxp7h3q/2/