Enabling a SpriteRenderer?

Hi, I'm learning Unity, and i've run into a problem when trying to enable one SpriteRenderer from a C# script.

I have one static object on my game with a rigidbody 2d and a box collider. When the player collides with this object I want to enable one UI element (a text board). The code I'm using is the next:

Code (CSharp):

1. public class ObjectController : MonoBehaviour
2. {
3.     public SpriteRenderer UI;
4.  
5.     void OnCollisionEnter2D(Collision2D collision)
6.     {
7.         Debug.Log("hello");
8.         UI.enabled = true;
9.     }
10. }

Then I've used the Inspector to drag and drop the SpriteRenderer element to the public variable of the script. When the player collides with the Object, I see on the console the logs "hello", but the SpriteRenderer dosn't change at all.

Any idea of what I could be doing wrong?

Thanks in advance guys,

 

UI.SetActive(true);