after patching a CE 220.127.116.11 with SUPEE-6788 (patching worked) we cannot see the data assigned with a category in the backend. By clicking on a category on the left side (tree) the form fileds on the right side remain emtpy, although there sure is data, because we see it in the frontend.
Additionally in the var/report directory an error ist created:
SQLSTATE[42S22]: Column not found: 1054 Unknown column '`main_table`.article_id' in 'where clause'...
I guess, it has something to do with that.
Can anyone give me a hint about how to solve this issue? Thank you very much.