Currently, JIRA Share issue option, allows the users to see all users as they type the username in the Share issue option field. It will be nice if it was possible to configure those users showing in the Share issue field to include only those users who have the right to view the issue.

Moreover, that a reporter of an issue can share the issue, e.g. by simple sending an URL in an email. Just like the current "Share Issue" function is working, though without the restriction that it's only possible to share an issue with existing users. The entire function could be available through some kind of "Global Permission" - something like "Allow users to send e-mails through Jira" - a small template like:

<Jira account> share an issue with you. Please take a look at <Jira URL>