OnClick() problem with Button script: "Deleting an array element will copy the complete array to all..."

The reason why this happens is because the way Unity handles editing multiple objects.

For instance, when you have a script with a string variable. You put that script on 3 different GameObjects and give them each a different value. Then you select all 3 GameObjects (now you are 'editing multiple objects') and when you modify the string. The result is that all strings will be modified.

Now with this array. When 'editing multiple objects', Unity doesn't look at each array item individually, but at the complete array as a whole. So if you then multi edit one item of the array, you are actually modifying the complete array. And therefore, sinse you are multi editing, you are multi editing all arrays.

I think you might be able to overcome this issue by writing a custom instector script. But this is tricky, sinse for instance you have the following setup:

• 1 array of length 2

• 1 array of length 2

• 1 array of length 6

And now you want to modify the item at index 5 of the third array. But the other 2 don't have this item at a different index, should they:

• add it?

• add index 2 till 5?

• Modify their own index 1 (as that is their last )?

• or just copy the entire array as Unity does?

As you can imagine, there is no 'good' solution in all situations. So therefore unity chooses to modify the array as a whole which I think is the best approach.

Also, sinse you are using the builtin Unity button and not a custom class for which you could be able to build a custom editor, I think you best (and easiest) option would be to simply not multi edit (i.e. remove the second item from one button at a time)...

Another (ugly) workaround could be something like this...

 public class SomeExtraFunctionality : MonoBehaviour
 {
     public UnityEvent myEvent;
 
     public void Start()
     {
         GetComponent<Button>().onClick.AddListener(myEvent.Invoke);
     }
 }

If you add this script to the button, even though the event on this script has the same issue. If you add 'item 2' to this script and the other items to the button, you could multi edit it without modifying the array on the button. Not really a solution to the problem, but depending on your situation it might be helpfull...