Update

Assets/Invector-3rdPersonController/ItemManager/Scripts/vSetFirstSelectable.cs

@@ -0,0 +1,44 @@
+using System.Collections;
+using UnityEngine;
+using UnityEngine.EventSystems;
+
+namespace Invector.vItemManager
+{
+    public class vSetFirstSelectable : MonoBehaviour
+    {
+        public GameObject firstSelectable;
+
+        [Tooltip("True: Execute Selection Handler Event - False: Execute Pointer Enter Handler Event")]
+        public bool callSelectHandle = true;
+
+        public void ApplyFirstSelectable(GameObject firstSelectable)
+        {
+            this.firstSelectable = firstSelectable;
+        }
+
+        void OnEnable()
+        {
+            StartCoroutine(SetSelectableHandle(firstSelectable));
+        }
+
+        IEnumerator SetSelectableHandle(GameObject target)
+        {
+            if (this.enabled)
+            {
+                yield return new WaitForEndOfFrame();
+                SetSelectable(target);
+            }
+        }
+
+        void SetSelectable(GameObject target)
+        {
+            var pointer = new PointerEventData(EventSystem.current);
+            ExecuteEvents.Execute(EventSystem.current.currentSelectedGameObject, pointer, ExecuteEvents.pointerExitHandler);
+            EventSystem.current.SetSelectedGameObject(target, new BaseEventData(EventSystem.current));
+            if(callSelectHandle)
+                ExecuteEvents.Execute(target, pointer, ExecuteEvents.selectHandler);
+            else
+                ExecuteEvents.Execute(target, pointer, ExecuteEvents.pointerEnterHandler);
+        }
+    }
+}