UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/50.0.2661.75 Safari/537.36

Steps to reproduce the problem:
1. Open browser and navigate to a scrollable page
2. Open another app, make sure it's window(s) and the mouse cursor are above chrome's (both maximized on same display is easiest). Scroll a bit in it.
3. Alt-tab back to chrome, scroll in it.

What is the expected behavior?
Chrome scrolls the page one step.

What went wrong?
Chrome scrolls the page one step, AND however much you scrolled in the other application.

Did this work before? Yes I don't remember.

Chrome version: 50.0.2661.75  Channel: stable
OS Version: Ubuntu 15.10 (GNOME)
Flash Version: Shockwave Flash 21.0 r0

Replicated in Chromium 49.0.2623.108, Chrome 50.0.2661.75