In the cluster creation flow, we have a step "Cluster network". 

We are asking users to choose subnet and then allowing to input the API Virtual IP and Ingress Virtual IP. 

The problem is that the user needs to type the whole IP inside the text field twice, while most of the time they will need to change the last number or the last two numbers of the selected subnet. It is a good idea to help users and pre-fill the "static" part of the IP and let the user type in the rest of it only.