             center.removeObserver(self, name: .midiObjectPropertyChanged, object: externalDevice)
         }
 
-        guard let midiContext = (NSApp.delegate as? AppController)?.midiContext else { fatalError() }
         destinations = CombinationOutputStream.destinationsInContext(midiContext)
         externalDevices = midiContext.externalDevices
 

    var trackingMIDIObject: MIDIObject?
    var speedOfTrackingMIDIObject: Int = 0

    func captureDestinationsAndExternalDevices() {
        let center = NotificationCenter.default


                midiObject.maxSysExSpeed = newValue

                // Work around bug where CoreMIDI doesn't pay attention to the new speed
                midiContext.forceCoreMIDIToUseNewSysExSpeed()
            }

