Scrolling up on touch device leaves blank "gap" in side nave at the bottom of the page

**Prerequisites**:
- Two or more pages of content so that when you scroll-up, the chrome in Chrome dissapears.

**Browsers**:
- Safari on iOS 9.3.4 (iPhone 5S)
- Chrome 52.0.2743.84 on iOS 9.3.4 (iPhone 5S)

**Repro**:
1. Load the side-nav page
2. Tap hamburger icon
3. Scroll-up side-nav and notice the "gap" at the bottom. This gap is as big as the chrome in Chrome. It's as if the bottom part of the side-nav isn't being repainted while scrolling.

Update: An even better fix would be if when scrolling the side-hav all touch events for the page content are blocked.