Ah, I already discovered how to solve this issue:
Apparently the arguments in the link are to long.
I copied the link that you get upon clicking ‘Remove entries from Database’ and splitted it into smaller parts so that it deletes each time about 100 items. Initially it should delete more than 800, this was to much to do at once.
Widget editing has already been disabled.
The only thing that solves it is if I uncheck ‘Enable the WYSIWYG editor’
Everything else has no impact 🙁
no, not the administration bar. i was talking about… the sidebar. I’m using the takteek theme, and there the sidebar1.
when you go to my site, the left bar with the navigation.