Edit button doesn't show up

I have exactly the same problem. I have spent the last four hours trying every conceivable combination of settings but I cannot get the Edit button/link to show up.

If I produce the appropriate URL in the format: /comment/edit/xxx (where xxx is the comment id) the User can edit the comment which shows that the permission has been granted. Despite this, the button will not show.

I am using Advanced Forum and flatcomment, both of which are enabled. I have tried disabling flatcomment but it does not help.

My chosen comment setting for my forum_topic content type is 'flat list - expanded'. I have tried every other setting but it makes no difference.

The edit button shows up for a member with 'administer comments' permission so the image required for the button obviously exists.

I am using the Forum Access module which does not grant any editing rights as I rely on the 'edit any forum topic' in Permissions for admins.

Can anyone help before I finally give up on what looked to be a very promising module?

I have, of course, searched all the issues. There is some ambiguity on one point which it would be helpful if you would clarify. On this issue:

http://drupal.org/node/1041862#comment-4012020

you show part of the code which includes:

// Hide the edit link if flat listing is enabled.

In your comment below you say:

"The edit link is gone is if b) the comment list is not flat. "

These two directly contradict each other.

Apparently, the advanced comments module does not do enough to flatten comments, or something related to this. I have been grueling over Drupal trying to figure this one out.

When I added this light module to FORCE flat comments, the edit button finally appears:
http://drupal.org/project/flatcomments