Discovered a bug with the moderation functions / moderation overlay. I created some test topics as shown below.
Notice the moderation checkboxes and the selected threads link which allows the moderation overlay to be used. Now when I make all 3 threads sticky this happens.
Notice the checkboxes are still present but the selected threads link has disappeared and clicking on the checkboxes no longer brings up the moderation overlay. Only seems to to happen when there are only sticky threads in a forum and no normal ones. Been confirmed by at least 1 other users.