As ist seems it is a problem between bootstrap 3 (used by the template) an bootstrap 2 (used by joomla). It seems there is an overrite neccesary for the template.
inbetween i am using a plugin (https://github.com/nielsnuebel/plg_system_nnedittemplate/releases/tag/v1.0.0) which uses other templates for content and module editing as an workarround.
But it seems to work only with the tiny editor and in the case you are edit pictures it is not so perfect....
maybe it helps to solve the problem.
best regards
kerstin

Hi Kerstin

Thank you for bringing this issue to our attention. I have just updated the Emani template, resolving this issue and installed the update to your Joomla installation. Your custom module editor should be now displayed with issue.

Ciaran

Hi Ciaran,
thank you very much for your outstanding support. It works perfect. Yor are great

Kerstin