Version: Version 52.0.2706.0 canary (64-bit)
OS: Windows

What steps will reproduce the problem?
(1) go http://output.jsbin.com/sidaquzumo
(2) drag over a user-select:none element.
(3) copy and paste to textarea

What is the expected output?
The user-select:none element should not be selection-painted and not be copied.

What do you see instead?
The element was copied.

Interoperability
FireFox: The element is not selection-painted and is not copied.
Edge: The element is selection-painted and is copied.