Unity UI adding EventTrigger staying after runtime?

So I am using this code to add eventTrigger listeners
https://docs.unity3d.com/ScriptReference/EventSystems.EventTrigger.html

Code (csharp):

1.  
2. trigger = GetComponent<EventTrigger>();
3. EventTrigger.Entry entry = new EventTrigger.Entry();
4. entry.eventID = EventTriggerType.PointerDown;
5. entry.callback.AddListener((data) => { OnPointerDownDelegate((PointerEventData)data); });
6. trigger.triggers.Add(entry);
7.  

I have an empty eventTrigger component added to my button



When I run in the editor, i can see the new event ...



but when you press STOP in the editor, the event trigger added remains. When I run it again, it adds another one...



Only just realised when looking at the button and finding 100 pointerDown event triggers in the list

Why are they staying if they are added in runtime?

Do they have to be removed when the game stops playing?

Thanks

 

Ah

I was following this hack to make an invisible button, extending Text

https://answers.unity.com/questions/801928/46-ui-making-a-button-transparent.html

So public class invisibleUiButton : Text was keeping those eventTriggers around. Will move to a new script.