I have upgraded from Confluence 3.5.9 to Confluence 6.7.2. Everything seems to work OK except for when i'm trying to add or edit a page. I can't see the title box and I can't resize the box. If you look at the attached image you can see something is not right with the editor box. This also prevents me from creating new pages, when I can't edit the title.

I have tested with different browsers (FF, Chrome, IE and Edge) with the same result.