Hi. I'm trying to write a simple custom editor for my action.
It's first time to write a playmaker editor.
Anyway. I read 'moveTowardActionEditor'. I couldn't fully understand but I wrote a simple editor.
This is my status.
1. I tried to visualize 'Vector3[] places' on the scene view using several Handles. - succeed
2. Of course, if I move a handle(for places[0]), The handle's position should be places[0] 's value. - failed
At first, it seems like success.
I can move a handle, the position places[0]'s value looks like updating on action editor. 
But, if I click some other object, then get back to my object(has the action), the places[0]'s value will change back to before.
In short, the handle's movement doesn't affect on the real value of variable.
this is my code.(custom editor)
        public override bool OnGUI()
        {
            return DrawDefaultInspector();
        }
        public override void OnSceneGUI()
        {
            var positionAction = (HutongGames.PlayMaker.Actions.myPositionAction)target;
            if (positionAction.updatePos()) {
                for (int i = 0; i < positionAction.places.Length; i++)
                {
                    Handles.Label(positionAction.places[i] + new Vector3(0, 1, 0), "place" + i);
                    positionAction.places[i] = Handles.PositionHandle(positionAction.places[i], Quaternion.identity);
                }
                if (GUI.changed)
                {
                    FsmEditor.Repaint(true);
                    FsmEditor.EditingActions();
                }
            }
        }
and this is part of my custom action code.
   [Tooltip("Various vector3 places.")]
   public Vector3[] places; 
//maybe i shoud do something in the action's code. right?
        public bool updatePos() {
            if (places.Length<=0)
            {
                return false;
            }
            else {
                return true;
            }
 // some action codes below.
            
        }
Oh...please help this poor man~!