UserAgent: Mozilla/5.0 (X11; CrOS x86_64 8530.81.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.103 Safari/537.36
Platform: 8530.81.0 (Official Build) stable-channel peppy

Steps to reproduce the problem:
1. Open an image in Files->Gallery
2. Wait, and notice that the thumbnails, etc. auto-hide
3. Move Pointer, notice that UI elements flash but no longer auto-hide
4.  Navigate to next image using arrow key (without moving pointer)
5. Wait, and notice that the thumbnails, etc. auto-hide (repeating from Step 2) 

What is the expected behavior?
UI elements should hide even if pointer is moved

What went wrong?
Not sure.  Worked fine until the latest Stable release update.

WebStore page: Files

Did this work before? Yes Last Stable release

Chrome version: 53.0.2785.103  Channel: stable
OS Version: 8530.81.0
Flash Version: Shockwave Flash 22.0 r0

HW: Acer C720 chromebook