Timeline: verticalScroll bug 4.17.0 - the content area slides downwards

Hi, I've found a bug while using a new very cool parameter verticalScroll : true. If set to true and there is enough space so no scroll bar is rendered - the content area just "slides" to the bottom of the timeline:

Here is a jsfiddle: http://jsfiddle.net/Lkskqz9q/3/