When a user interacts with the eye, we want to display a list of users that will be able to see their message to that specific person. This list of users is arbitrarily long. It could just be a few people, or it could be a dozen. It will be different for each recipient.
Because the list can potentially be long, having a hover tooltip doesn't seem like the right behavior since the list could easily past the modal. An alternate solution I can think of is to either replace the modal contents with the list (with an easy way to get back to the compose mode) or do some kind of modal within a modal thing (that doesn't sound so good to me).
Are there common conventions or practices that people do in this situation?