Version: <observed in Version 49>
OS: <ChromeOS>

What steps will reproduce the problem?
(1)Open "Files" window in user profile u1
(2)Right click the title bar and click on "move window to ...(user u2)"
(3)The "Files" window is opened in the u2 desktop
(4)Go to either u1 or u2, it seems like "Files" window is not opened in both user's desktop: "Close" item is disappeared from context menu of shelf for both users.

What is the expected output?
Since "Files" window is moved to u2 desktop, u2 can close "Files" window from the context menu.

What do you see instead?
Both u1 and u2 cannot close the "Files" window from the shelf

Please use labels and text to provide additional information.