I want to disable permission or the horizon button or whatever best way to not allow end users to "Release floating IP" because I want them to stick with assigned IP and not releasing them because of some regulatory process. 

Not sure what is the best way to have this level of control. I found neutron policy delete_floatingip: but is this the correct way to implement this policy? 

OR 

Does Horizon have some level of ACL to remove buttons or disable it?

Looking for advice or clues. 

Thanks!