Hi Nanske
What kind of set up do you have? Where is your wp-content folder located is it the standards install?
Are you using WordPress multi-site. If I can replicate the problem I can fix it. But right now I don’t seem to be able to. If you have a solution to the issue let me know and I would be more then happy to update the code to fix it. I would like to get to the bottom of this issue.