Auto Select On Enable

selectonenable

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;

public class SelectOnEnable : MonoBehaviour
{
    void OnEnable()
    {
        // clear any selected objects
        EventSystem.current.SetSelectedGameObject(null);
        // set new selected object
        EventSystem.current.SetSelectedGameObject(this.gameObject);
    }
}

selectonenable.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;

public class SelectOnEnable : MonoBehaviour
{
    void OnEnable()
    {
        // clear any selected objects
        EventSystem.current.SetSelectedGameObject(null);
        // set new selected object
        EventSystem.current.SetSelectedGameObject(this.gameObject);
    }
}