Unable to delete interface

[rowdybeans]

I am sure as I'm new to zabbix I am missing something simple. I've searched the documentation, but haven't found the solution.

I am trying to delete an interface from a host. It is an snmp agent. Under configuration, host, items, there is a list of all the interfaces. I would like to remove the unused ones, but the button to select the item is greyed out.

[Semiadmin]

If interfaceces were got by LLD, they may be only disabled form a host, not deleted. Select by button for this items unsupported, this option promised in version 3.2.