UserAgent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.87 Safari/537.36

Steps to reproduce the problem:
1. Create a chrome panel (https://www.chromium.org/developers/design-documents/extensions/proposed-changes/apis-under-development/panels) 
2. Using the mouse, move the panel out of the "magnetic" area (bottom-right in Windows 10), so that it floats in the screen.
3. Move another window on top.

What is the expected behavior?
The panel should remain "always on top" per spec.

What went wrong?
It is no longer "always on top".
If you move it back to the "magnetic" screen area, it becomes again "always on top". In Windows 10, that is only the bottom-right area. Other areas are "magnetic", like the right screen edge, but do not turn the windows again into "always on top".

Did this work before? N/A 

Chrome version: 49.0.2623.87  Channel: stable
OS Version: 10.0
Flash Version: Shockwave Flash 21.0 r0

In recent versions of Chrome this did not happen. I know that as I'm the developer of a popular Chrome extension that never received issues about this and now suddenly users are reporting this issue.