Scroll Header Panel flowing over panel scroll bar

[tjsavage]

I was looking at the Demo at, http://www.polymer-project.org/components/paper-elements/demo.html#core-scroll-header-panel. The hero flows over the scroll bar.

http://imgur.com/jADecK7

Same for all browsers below.
Chrome 35.0.1916.153 m
Firefox 30.0
IE 11.0.9431.0IS

The effect is that you can't grab the scroll control to slide down, you must click on the scroll bar somewhere and jump the scroll control to somewhere under the hero so that the scroll control is visible.

Applying #headerContainer { calc(100% - 17px); } seems to fix the issue.