However if I open a topic via link to first post (that is available by clicking #1 near the first post), all my posts have edit button, as petermad said, but these buttons only open edit form for first post, for other old posts I see "You can no longer edit or delete that post.".
If I open a topic via link to any post except first one (by middle-clicking #nn near the post or by opening an url that is displayed in a message on left-click), edit buttons are missing again for all old posts including the first ones.
So, currently there is a way to edit first posts, but it is not quite transparent.
