subscribe to bug

[greeniekin]

I was wondering if there was a way to have the option for users to subscribe to a bug. In the config area I saw the options to have emails sent out to bug reporter, assignee and people who comment. Though I couldn't see a way to simply click subscribe to a bug without interacting with the bug. Similar to what I think bugzilla does. Where you can even unsubscribe. I had a quick Google though I didn't find anything.
How can i get a similar feature?

[atrol]

There is a button "Monitor Issue" when you view an issue.
And there is a button "End Monitoring" to stop it.

[fredi]

I have similar problem. There is "Users monitoring this issue" but only developer can add users there. Can i allow reporter add users into Users monitoring this issue? My mantis version is 1.2.0.RC2.
Thanks for advice.