DEFENDER: disable Fileeditor showing up in frontend!

Hi Team

after clicking to correct the disable fileditor in defender the following message shows up in frontened - This should actually not be happen ;-(

https://www.dropbox.com/s/o96r9j8o9wnzbx8/Screenshot%202017-01-13%2010.22.52.png?dl=0

Kind regards

Andi