Issue: Private attachments

Sometimes, even the issue is open to the public, attachments should be hidden sometimes.

In my forum I use the projects to document my work on the forum and the server. My users can see the issues and comment them. But sometimes, even the issue can be viewed by anyone, I want to keep an attachment hidden. It would be nice to be able to give every single attachment separately the private flag.

(I have to select a version, so I used the latest version, even I know it is too late to implement there)