The [-] collapses your view of the thread. The flag link appears when you have sufficient karma (I don’t recall the threshold). Click on the time stamp for the

The [-] collapses your view of the thread. The flag link appears when you have sufficient karma (I don’t recall the threshold). Click on the time stamp for the comment you want to act on. If you have enough karma, the flag link appears between the “parent” and “favorite” links.