UserAgent: Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/50.0.2661.87 Safari/537.36

Example URL:
http://s584381281.onlinehome.fr/test/index2.php

Steps to reproduce the problem:
1. Go to http://s584381281.onlinehome.fr/test/index2.php in a Maximized Chrome windows
2. Open a new tab
3. Drag the tab with the circle out of the chrome window to make a new window with the tab.
4. The canvas disappears
5. Drag it again: the canvas re-appears.

What is the expected behavior?
The canvas to not disappear.

What went wrong?
I don't know.

Does it occur on multiple sites: N/A

Is it a problem with a plugin? No 

Did this work before? N/A 

Does this work in other browsers? Yes 

Chrome version: 50.0.2661.87  Channel: stable
OS Version: 6.3
Flash Version: Shockwave Flash 21.0 r0

I tried it on this site with firefox and it works,
I tried it on other canvases with chrome it works.