Those are not both midi tracks.
inspector_instrument.png shows an Instrument Track, which will never have a midi fader. (and is a hybrid of midi and audio)
inspector_rack.png shows a Midi Track. (A midi track can be routed to the VST Rack, an external device or an Instrument Track)
New to 7.5 is the possibility to route Midi Tracks to Instrument Tracks, also, Instrument Tracks now appear in the VST Rack.
You can add midi tracks and route them to that instrument track, that’s how you will get a midi fader on that track.
Also, and I mean no disrespect, It might be profitable for you to read through the Track Instruments section in “New Features in Cubase 7.5” doc that was included in the install. That’s the best source for this info.