I did a lot of things and the checkbox in the top right in the inspector is gone. It looks differently now. No more dropdowns for layers but Textfields. Unfortunately I wasnt paying attention and dont know which of my actions changed the design of the inspector thing. I am talking about the component every gameobject has. The one above the transform. Seen in this link: http://www.fotos-hochladen.net/view/aaavbe9tu0i1z.jpg
Okay so I found out what I did. I used a custom editor which i made type of Gameobject just so its OnSceneGUI would work all the time. Unfortunately this fucked up all gameobject Inspectors so i am going to make it use the standard inspector and all should be fine.