OnMouseDown problem when childing an object

Hello, so I've been trying to get the coordinates of the mouse within the object.

Code (csharp):

1. void OnMouseDown () {
2.         print(Input.mousePosition);
3.     }

This simply works normally. But when I make this object a child of some other object and it suddently stops working. For example I have an gameObject called front, It has BoxCollider2D and the script attached. I click to the object and I see my mousePosition but when I take this object and make child of another object it stops giving me the mousePosition. I try it with the 3D Box Collider and It works regardless of childing. Is this a bug or am I doing something wrong?

Edit: I found a solution but still, it's weird that 3d Box Collider returns the value and 2d doesn't.
Solution: http://forum.unity3d.com/threads/29228-OnMouseDown()-Child-Colliders-issue-solved