Sometimes OnMouseDown() method in Unity executes, sometimes it does not

Question

So I have this code attached to a Quad.

public class ShapeGrid : MonoBehaviour {

public GameObject[] shapes;

void Start(){
    GameObject[,] shapeGrid = ne         


        

Answer 1

Probably you have to add colliders to all of objects because OnMouse events are based on collisions. Here is detailed info: Unity Docs - OnMouseDown

Edit: after some talks we find out that the problem was caused by Instantiate method.

It's allways a better way to fill all of parameters in Instantiate method e.g

Instantiate(prefab, Vector3.zero, Quaternion.Identity)

if you want, you could change any of these parameters after instantiating object.