When you say "delete", do you mean move to trash?
1. I had that problem too and found the fix in the css file (main.css, I think). Look for something like messagelist. Better yet, copy it from RC1, which is set correctly.
2. I can drag and drop without a problem. I drag from any folder to trash and they stay in trash until I empty it, and that works too.
3. The drop down doesn't work for me either.