Sidebar moved down under page content

Hello,

For our customer im building a new website in test mode. Suddenly since yesterday, the sidebar widgets moved to the end of the page content. There is still a sidebar visible, but it’s empty. I have literally checked every setting, checked clashes with plugins like ubermenu, etc. I have not changed much yesterday, so i have no clue what it could be.

http://www.pixhoster.info/f/2016-08/6b25ad37aa97befe676d150eb0fc78b4.png

Do you have any idea what it could be or where to look?

Thanks so much

Ticket