ok, I have found the files for the remaining tabs to adressed as edit_others.php and edit_attachments.php
I have moved the recurrency and image fieldsets to the edit.php as the remaing fieldsets of that tab - which was possible and working. But as soon as I hide the other tab, it doubled on the create event page...
So I must be doing something wrong. What could that be?
I am not a professional Joomla user, but apparently I am very good at hinding that. I know some CSS, something about overrides, but please do not count on it ...
JEM 2.1.4 on Joomla 3.4.3