I have read the documentation about sharing an issue and I can't find the button to share an issue with another JIRA user of the same project.
Also I can't share a comment with the "@ option. When I type the @" and the fist letters of the user name, it doesn't show the list, and doesn't mark as a link.
I attached an screen capture to explain better the button I can't see.
I'm using the cloud version. 
