@Nuxwin
Thx for your reply.
Currently I am using a server hosted by Strato. Strato preconfigured the interface file with ipv4 dhcp which is working very well. I think that is the reason why I-MSCP wants to add the IP Adresse.
I know you want to make I-MSCP as user friendly as possible. But for me it would be great if there are possibilities to disable some things like this.