Once the Protoflux has been selected, make an empty Slot using the Inspector. This will be the slot the Protoflux is packed into. To then pack the Protoflux, grab the slot using the left side of the Inspector so that it's name is above the ProtoFlux Tool. While you are grabbing it, open your Context menu and select Pack Into. Once packed, the Protoflux will still function like normal, but will no longer show its visuals and will apply some optimizations.