1) I had access to a very useful Trash button that let me delete threads from the front-end. I can't find that anymore or find a way to enable it.
Please let us know do you use the wpDiscuz Frontend Moderation add-on? If yes you just need to hove over the comment thread to see the "Manage Comment" button, then simply click on it to see moderation option(included delete comment). Screenshot below:
In the core wpDiscuz plugin, you can delete the comment by clicking in the "My content and settings" button, go to the "Activity" tab, and delete the comment you need. Screenshots below:
2) Each of the discussion items has a big block of empty space now:
For farther support please register and open a new support topic in the wpDiscuz.com support forum, and leave the example URL. Here we only support issues related to wpDiscuz paid addons.