When performing a right-click on a model or container in Spectrum OneClick running on macOS, the menu does not appear instantly as in the past but can take many seconds (maybe 5 or 6), slowing responsiveness.
When a Java app calls the java.net.InetAddr.getLocalHost() class, it attempts a reverse lookup of this address and checks that it maps back to the input host name and this slows it down when its not explicitly defined in the /etc/hosts file of macOS Sierra.
Spectrum with macOS client
To resolve this, explicitly name the mac in the /etc/hosts file. For example, if his Mac's host name is macPro, then, list it as;
127.0.0.1 localhost macPro.local
::1 localhost macPro.local