public void OnEnable()
 {
     markerGroup = FindObjectOfType <MarkerGroupBehaviour>();
     if (PrefabUtility.GetPrefabType(target) == PrefabType.Prefab)
     {
         return;
     }
 }
        public override void OnInspectorGUI()
        {
            if (PrefabUtility.GetPrefabType(target) == PrefabType.Prefab)
            {
                return;
            }

            bool isDirty = false;

            markerGroupBehaviour = (MarkerGroupBehaviour)target;

            EditorGUILayout.Separator();

            float oldMarkerSize = markerGroupBehaviour.MarkerGroupSize;
            float newMarkerSize = EditorGUILayout.FloatField("Marker Size : ", markerGroupBehaviour.MarkerGroupSize);

            if (oldMarkerSize != newMarkerSize)
            {
                markerGroupBehaviour.MarkerGroupSize = newMarkerSize;
                isDirty = true;
            }

            EditorGUILayout.Separator();

            bool oldApplyAll = markerGroupBehaviour.ApplyAll;
            bool newApplyAll = EditorGUILayout.Toggle("Apply All : ", markerGroupBehaviour.ApplyAll);

            if (oldApplyAll != newApplyAll)
            {
                markerGroupBehaviour.ApplyAll = newApplyAll;
                isDirty = true;
            }

            if (GUI.changed && isDirty)
            {
                if (markerGroupBehaviour.ApplyAll)
                {
                    foreach (var tracker in markerTrackerBehaviour)
                    {
                        tracker.MarkerSize = markerGroupBehaviour.MarkerGroupSize;
                        EditorUtility.SetDirty(tracker);
                    }
                }

                EditorUtility.SetDirty(markerGroupBehaviour);
                EditorSceneManager.MarkSceneDirty(EditorSceneManager.GetActiveScene());
                SceneManager.Instance.SceneUpdated();
            }
        }