Strange obstructive UI element which I can't remove

[itsamee 0]

Hello

Right after todays server restart my interface got completely messed up. After I sorted everything out I noticed that there was this odd UI element that has never been there before. I use quite a lot of addons and I'm sure its not any of the new ones i have added. When I rightclick it it only lets me adjust it's transparency and it doesn't seem to do anything other than blocking the clicks to part of the screen its on.

Here is a picture of it, as well as complete list of every addon I have in my addons folder. There are many that I have disabled but haven't got around deleting yet.

http://imgur.com/a/xgtzT

 

[crum 0]

This is the default blizz UI Party Background element. You can find that in your interface settings :)

[itsamee 0]

Ok, thanks for help :)