Just for everyone who might have the same problem one day, I found the following solution:
The Screen had been used with the older (now wrong) layout.
Somewhere this layout had still been saved (don't ask me where, I wasn't able to find it...)
In the end I deleted the old view, and created a new one, with a slightly different name (instead of finlimgrpv it is now finlimgrv) -> Now it works the way it is supposed to.
If anyone ever finds the spot, where the wrong layout is still saved, I would appreciate the information.
Thanks
