It's always been that way with the double screen - I've never known anything different.
As to the add-on, here's what happened (to my limited understanding):
The add-on is not listed in the add-ons section I think because this all happened immediately when I tried to upload the xml file for that add-on. I got the error message that the files necessary for the add-on were not found so when I tried to do upload the xml file again that's when I realized the site had crashed. What do you want me to do about it as it stands? I really do not wish to upload that add-on again to my server . . .