UserAgent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2866.0 Safari/537.36

Example URL:
http://codepen.io/dominikschreiber/pen/gwLZQp

Steps to reproduce the problem:
1. open http://codepen.io/dominikschreiber/pen/gwLZQp
2. observe that #scrollcontainer has a horizontal scrollbar
3. if you add overflow-y:hidden to #should-not-have-a-scrollbar, the horizontal scrollbar vanishes

What is the expected behavior?
there should be no visible scrollbars as the #content fits into the #scrollcontainer

What went wrong?
the horizontal scrollbar appears on the #scrollcontainer.

I assume something goes wrong when deciding to show the horizontal scrollbar. It seems that if "width of content" + "width of a potential vertical scrollbar" < "width of parent", a horizontal scrollbar is shown, although the vertical scrollbar is not needed.

If you set overflow-y:hidden on the #scrollcontainer or decrease the width of the #content so that a vertical scrollbar would fit as well, the horizontal scrollbar goes away.

Does it occur on multiple sites: Yes

Is it a problem with a plugin? No 

Did this work before? Yes worked in Chrome 51, wrong behavior appeared in Chrome 52 (stable)

Does this work in other browsers? Yes 

Chrome version: 55.0.2866.0  Channel: canary
OS Version: 10.0
Flash Version: Shockwave Flash 23.0 r0
 

Deleted: chrome-52_horizontal-scrollbar.png 1.0 KB

	chrome-52_horizontal-scrollbar.png 1.0 KB View Download