Hi @Ronny Lewandowski,
Unfortunately, we have not received any reports of the impact of the new List-Design on Forms-Customizer.
Since we don't have more in-depth information on the impact of the new List-Design on Forms-Customizer. I recommend that you open a ticket, as someone more specialized there may be able to help you find the cause of the problem.
Please accept my sincerely apologize for any in convenience this may cause. Thank you for your kind understanding.
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