Unity Editor mouse position to world point

Hi,

I wanna create an editor script. With that, user can add some assets to the scene by clicking on the screen. (NOT IN GAME, IN EDITOR) To do this, I need to find the mouse position from SCENE CAMERA to world point. I did some research and made a POC. I pass the best answer I could found. But the the problem is, it is not working, it looks like an exponential offset happening to the world position. I don't know what the problem is and there is no clear answer I could found in the internet. Could some one help me?

Here is my Editor Code:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEditor;
 
 [CustomEditor(typeof(LevelManager))]
 public class LevelManagerEditor : Editor {
     SerializedProperty position;
 
     void OnEnable()
     {
         position = this.serializedObject.FindProperty("position");
     }
     
     public void OnSceneGUI(){
         Vector2 mousePos = Event.current.mousePosition;
                 mousePos.y = Camera.current.pixelHeight - mousePos.y;
         
         Vector3 worldPosition = Camera.current.ScreenToWorldPoint(mousePos);
                 worldPosition.z = 0;
 
         position.vector3Value = worldPosition;
 
         serializedObject.ApplyModifiedProperties();
     }
 }
 

Here is Game Code:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class LevelManager : MonoBehaviour {
     public Vector3 position;
 
     void OnDrawGizmos()
     {
         Gizmos.color = Color.red;
         Gizmos.DrawCube(position, Vector3.one * .5f);
     }
 }