Why isn't this gameObject persisting?

The gameObject tile_residence is fine in the Start method. But then later in OnMouseDown, it has become null.

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class Checker : MonoBehaviour
6. {
7.     //
8.     //  Place checker on this tile during initial board setup.  Setup_Tile set in Unity editor.
9.     //
10.     public GameObject Setup_Tile;
11.  
12.     //
13.     //  Tile this checker currently resides at
14.     //
15.     GameObject tile_residence;
16.  
17.     // Start is called before the first frame update
18.     void Start()
19.     {
20.         transform.position = Setup_Tile.transform.position;
21.  
22.         tile_residence = Setup_Tile;                                        // Set this checker's residence tile
23.         Debug.Log(tile_residence.transform.name);
24.  
25.         tile_residence.GetComponent<Tile>().resident_checker = gameObject;  // Set this checker as the resident of the residence tile
26.     }
27.  
28.     // Update is called once per frame
29.     void Update()
30.     {
31.        
32.     }
33.  
34.     void OnMouseDown()
35.     {
36.         //Debug.Log(transform.parent.name + ", " + transform.name);
37.  
38.         if (tile_residence == null)
39.         {
40.             Debug.Log("tile_residence == null");
41.  
42.         }
43.  
44.         //Debug.Log(tile_residence.transform.name);
45.         /*
46.         if (this.Setup_Tile != null)
47.         {
48.             //Debug.Log(Setup_Tile.name);
49.  
50.             //Debug.Log(tile_residence.transform.name);
51.  
52.             //Debug.Log(tile_residence.GetComponent<Tile>().isSourceTile);
53.         }
54.         */
55.     }
56. }
57.  

 

Maybe I can work around this and just use the original Setup_Tiles without making copies. But I'd still be interested in knowing the problem here, just for my own education, if anyone knows.

 

No, apparently cannot change objects set in Unity editor...

 

I think I have a clue. It seems to be a parent-child thing. The tutorial guy said it would save me a TON of trouble if I had tile objects contained in tile container objects. So far it's been just the opposite.

 

Got it. Required the line...

Code (CSharp):

1.         Debug.Log(transform.parent.GetComponent<Checker>().tile_residence);
2.  
3.  

That was a tough nut. Learned something about Unity in the process.