protected virtual void OnDisable()
 {
     graph.onExposedParameterListChanged -= UpdateExposedParameters;
     graph.onExposedParameterModified    -= UpdateExposedParameters;
     exposedParameterFactory?.Dispose(); //  Graphs that created in GraphBehaviour sometimes gives null ref.
     exposedParameterFactory = null;
 }
 protected virtual void OnEnable()
 {
     graph = target as BaseGraph;
     graph.onExposedParameterListChanged += UpdateExposedParameters;
     graph.onExposedParameterModified    += UpdateExposedParameters;
     if (exposedParameterFactory == null)
     {
         exposedParameterFactory = new ExposedParameterFieldFactory(graph);
     }
 }